WO2015152483A1 - Graphene reference deriving method, nano thin film analysis method using same, x-ray analysis apparatus, and x-ray analysis method for graphene having extremely fine thickness - Google Patents

Graphene reference deriving method, nano thin film analysis method using same, x-ray analysis apparatus, and x-ray analysis method for graphene having extremely fine thickness Download PDF

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WO2015152483A1
WO2015152483A1 PCT/KR2014/010364 KR2014010364W WO2015152483A1 WO 2015152483 A1 WO2015152483 A1 WO 2015152483A1 KR 2014010364 W KR2014010364 W KR 2014010364W WO 2015152483 A1 WO2015152483 A1 WO 2015152483A1
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graphene
ray
thickness
specimen
layers
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PCT/KR2014/010364
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French (fr)
Korean (ko)
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허승헌
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한국세라믹기술원
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Priority claimed from KR20140039101A external-priority patent/KR101494359B1/en
Priority claimed from KR1020140066946A external-priority patent/KR101538037B1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B15/00—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons
    • G01B15/02—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons for measuring thickness
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
    • G01N23/207—Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/61—Specific applications or type of materials thin films, coatings

Definitions

  • the present invention derives the effective data by accurately measuring the graphene thickness having the ultra-fine thickness of atomic-molecular-nano units, which has remained difficult until now, and only theoretically, by the X-ray diffraction (XRD) method. And a graphene reference derivation method for determining the thickness (number of layers) of unknown graphene samples, the thickness of an unknown nano thin film, the size of nanocrystals (average value, distribution, etc.) It relates to a nano thin film analysis method used.
  • the present invention relates to an X-ray analyzer for analyzing an ultra-fine thin film remaining in the unknown region and a crystallographic analysis method of the ultra-thin graphene (thickness 0.35nm ⁇ 3nm) using X-rays.
  • X-ray analysis of the material is very important.
  • Representative X-ray analysis methods include X-ray scattering, X-ray reflection, X-ray absorption, X-ray fluorescence, X-ray morphology and topology analysis (imaging), and X-ray diffraction.
  • Recent advances in equipment technology have enabled X-ray analysis of thin films of several nm thickness and nanograins of several nm size.
  • single crystal films of less than about 3nm and nanograin analysis methods having extremely small thickness and size of less than 2 ⁇ 3nm are considered to be very difficult with current X-ray analysis technology, and overcoming them has become a next-generation technology roadmap. This roadmap is very important.
  • the difficulty of X-ray analysis for a 0.5-3 nm thick crystal film is due to the following four reasons.
  • the reason for the above (1) will be described in detail. Whether thin or nanoparticles, atoms and molecules are united in nucleation, and these nuclei grow through collisions. At this time, the minimum nucleus size that can be obtained, that is, the minimum nanoparticle size is more than 3nm. That is, it is very difficult to obtain nanoparticles of 3 nm or less. This is due to the spontaneous nature of growth in larger forms, and the thermodynamic stability of the nanoparticles depends largely on the size of the particles (this is also relevant for reason (2) above).
  • Nanoparticles or nanofilms below 3nm are extremely thermodynamically unstable and are highly reactive with low thermal energy (a lot of samples change spontaneously at room temperature) and humidity, resulting in changes or completely different states. Therefore, a change may occur during X-ray measurement. Therefore, in the case of the extreme thin film, the inherent physical properties are lost and no result or wrong result is obtained.
  • Graphene as an extreme thin film is a new material having 1 to 10 layers (3 nm or less in thickness) that can exhibit quantum mechanical properties (distinct from graphite and nano carbon). Graphene plays many roles in materials and academic fields because of its excellent electrical properties, mechanical strength, and thermal conductivity.
  • Graphene can be largely classified into two types of thin graphene, which is obtained by pyrolysis deposition (CVD) of hydrocarbon, and powdered graphene obtained through physicochemical exfoliation of graphite. As the number of layers increases, the graphene changes its electronic structure and quantum mechanical properties to express new properties. Therefore, it is very important to find out the number of layers of graphene and to study the properties of each layer.
  • CVD pyrolysis deposition
  • the technique of making a uniform single layer is quite reliable and is typically made of roll-to-roll (R2R) on a large area copper (Cu) foil.
  • the single layer graphene is removed from the copper foil through etching, and the technology of transferring it to a desired substrate by attaching it to a polymer such as PDMS, that is, a transfer technology, is very advanced and is now at the stage of commercialization.
  • a polymer such as PDMS
  • a problem occurs in that the crystallization phenomenon occurs due to oxidation reaction (-OH production) and immersion of graphene oxygen and moisture.
  • multilayered graphene having two or more layers has not been made reliably because, when another carbon atom is grown on the single-layered graphene, the degree of freedom of carbon-carbon bonds in the vertical direction other than the horizontal direction is rapidly increased. (Increased entropy, increased degrees of freedom) This is because control of the number of layers becomes impossible. That is, the manufacturing mechanism of the multilayer graphene film is different from the monolayer graphene manufacturing process that induces the Cu-C bond to the maximum. For this reason, there are few studies on the physical properties of graphene layers, and of course, no method of measuring the number of graphene layers has been developed.
  • graphene powder is usually made of a multilayer film because it is produced by peeling graphite, but the number of layers, such as the edge portion, the edge portion, and the center portion, are all different. In other words, even one graphene powder having a two-dimensional planar structure has a different layer number distribution. Also the layer number distribution between the graphene powders is different. Of course, no measurement method for knowing the average graphene layer number or layer number distribution of the entire powder has been developed.
  • X-ray diffraction is a method of analyzing the X-ray diffracted by satisfying Bragg's law (Cragity law (Cullity, 1978)) for a specific crystal plane with respect to the incident X-rays is represented by the following [Equation 1] .
  • ⁇ is the X-ray wavelength
  • ⁇ is the diffraction angle
  • n is the order of diffraction peaks expressed as an integer
  • d is the interplanar distance (interval) of the grating
  • (hkl) is the Miller index of the crystal plane.
  • Equation 2 The thickness of the crystal plane by the Sherrer's equation (Cullity, 1978) is expressed by Equation 2 below.
  • D is a constant of the crystal surface
  • K is a constant (typically 0.89) depending on the shape of the grain
  • ⁇ is the X-ray wavelength
  • B is FWHM (full width at half maximum)
  • ⁇ is the diffraction angle
  • the present invention is to provide a method for deriving the effective information on the graphene thickness including the full width at half maximum (FWHM) and the interlayer spacing by obtaining the XRD peak according to the absolute graphene layer number.
  • FWHM full width at half maximum
  • the thickness is too thin (1 layer (3.5 kV or less), 2 layer ( ⁇ 7 kPa), 3 layer ( ⁇ 10.5 kPa), 4 layer ( ⁇ 14 ⁇ ), 5 layers ( ⁇ 17.5 ⁇ ), 6 layers ( ⁇ 21 ⁇ ), 7 layers ( ⁇ 24.5 ⁇ ) ⁇ Peaks cannot be obtained by conventional XRD measurement methods, and there are almost no XRD studies on these.
  • the XRD information is analyzed to determine the number of graphene layers 1 layer, 2 layers, 3 layers.
  • the graphene thin film is grown or stacked on the substrate in the form of a single crystal, if there is an orientated Crysta facet perpendicular to the substrate, only the crystal peak can be obtained by the conventional method. Grazing incident small-angle X-ray method was used to omit another crystalline surface hidden inside the membrane. In the case of graphene, there is no research on this. Therefore, when the surface perpendicular to the substrate on which the graphene thin film is formed, that is, the graphene (002) surface becomes a preferential crystal surface, the other (hkl) surface is hidden inside the film. Diffraction peaks on surfaces other than the graphene (002) crystal plane provide information about the graphene unit lattice.
  • a graphene reference derivation method according to a method of obtaining graphene (002) peaks per layer number through XRD method, a graphene thickness measurement method, and a method of obtaining other graphene (hkl) peaks through this method And to provide a nano thin film analysis method using the same.
  • a peak of one (002) crystal plane for each thickness is applied by applying various X-ray sources, detection apparatuses, and measurement methods to seven types of graphene crystals having a thickness of 3 nm or less, specifically, 3.5 ⁇ to 2.5 nm. To obtain the rado.
  • the present invention is to provide a method for obtaining important crystallographic information of the extreme thin film crystals from the (002) crystal surface of the extreme thin film graphene by thickness.
  • the present invention is a step of (a) preparing a reference graphene defined by the number of layers; (b) performing XRD measurements on the reference graphene to obtain diffraction peaks of the graphene crystal plane having a specific Miller index; And (c) deriving valid information on the graphene thickness including full width at half maximum (FWHM) and interlayer spacing from diffraction peaks of the graphene crystal plane having the Miller index. It provides a graphene reference derivation method comprising a.
  • step (a) it is possible to obtain a reference graphene defined by the number of layers by stacking single layer graphene.
  • the rocking curve of the crystal plane having a specific Miller index may be first determined before setting the X-ray irradiation angle to check the orientation.
  • the X-ray irradiation angle may be set within the angle range derived according to the following [Emission Angle Derivation Formula].
  • a GI SAXS measuring method may be performed when XRD of the reference graphene is measured, thereby obtaining diffraction peaks of the remaining crystal surfaces except for the crystal surface with Miller index (002).
  • parallel beam X-ray optics may be used to perform XRD measurement on the reference graphene, and the XRD measurement may be performed in 2theta (theta) - ⁇ (omega) mode. Can be.
  • the diffraction peak of the crystal plane with the Miller index (002) can be obtained when XRD is measured with respect to the reference graphene.
  • parallel beam X-ray optics (Parallel beam X-ray) optics) can be used to perform XRD measurements on the reference graphene, and the XRD measurement can be performed in 2theta (theta) - ⁇ (omega) mode.
  • the effective information may be derived by performing a peak fitting on the peaks of the number of layers of the reference graphene using a Gaussian function or a Lorentian function.
  • the rocking curve of the graphene crystal surface having the Miller index (002) is first measured to confirm the orientation, and the X-ray irradiation angle is determined according to the following [Emission Angle Derivation Formula]. It can be set within the derived angle range.
  • step (c) it is possible to derive the interlayer spacing (d002) of the reference graphene by the following [interlayer spacing derivation formula].
  • n degree of diffraction peak expressed as an integer
  • the present invention further comprises the step (d) of creating a calibration curve based on the valid information.
  • a graphene reference derivation method is included.
  • the present invention "(A) performing the XRD measurement on the nano thin film to be analyzed; And (B) measuring data including the thickness of the analyte nano thin film by comparing the XRD measurement result with a calibration curve prepared according to the graphene reference derivation method; It provides together with the "nano thin film analysis method characterized in that it further comprises.
  • the data of step (B) may include the graphene layer number and thickness of the analysis target graphene film.
  • the calibration curve of step (B) is made under the condition that the FWHM for each layer of the reference graphene meets the following [Derivation range], and when measuring the graphene layer number of the graphene film to be analyzed, the Miller index ( When the diffraction peak of the graphene crystal plane of 002) is observed, the number of graphene layers can be derived from the calibration curve.
  • the thickness of the graphene film to be analyzed may be measured by the following [graphene thickness calculation formula 1] or [graphene thickness calculation formula 2].
  • Thickness of the graphene film to be analyzed based on the distance between atomic centers (D1) d 002 ⁇ (N L -1)
  • N L Number of graphene layers in the graphene film to be analyzed
  • N L Number of graphene layers in the graphene film to be analyzed
  • the calibration curve of step (B) is the y-axis FWHM for each layer of the reference graphene, and the inverse (1 / D) of the graphene thickness obtained from the thickness (D) of the reference graphene as the x-axis
  • the conditions of the obtained straight line 14-40 and y-intercept -2-2 can be satisfied.
  • the present invention has been solved by using an ultra-thin graphene, which is a kind of ultra-thin film material.
  • an ultra-thin graphene which is a kind of ultra-thin film material.
  • seven specimen candidates with a clear definition of thickness and a difference of about 3.5 nm in thickness were derived and the X-ray analysis method was established accordingly.
  • the ultra-thin graphene specimens specifically derived are 1 layer (3.5 ⁇ or less), 2 layer ( ⁇ 7 ⁇ ), 3 layer ( ⁇ 10.5 ⁇ ), 4 layer ( ⁇ 14 ⁇ ), 5 layer ( ⁇ 17.5 ⁇ ) , 6th floor ( ⁇ 21 ⁇ ), 7th floor ( ⁇ 24.5 ⁇ ) ⁇ .
  • the number of graphene layers is 1 to 10 layers, and the size of the specimen is 0.3 cm ⁇ 0.3 cm or more.
  • the essential X-ray irradiation apparatus within the above condition ranges are parallel beam X-ray optics, array type detector, ⁇ -2 ⁇ measuring method, rocking curve measuring method, X-ray irradiator rotating method, specimen rotating method, Detector rotation method, graphene transmission X-ray, X-ray crystal diffraction method of graphene crystal, diffraction method of graphene (002) specific crystal plane, X-ray diffraction apparatus overall components, and the like.
  • the present invention is an X-ray analysis apparatus for satisfying the above conditions, "the temperature control 278 ⁇ 328 ° K and humidity conditions less than 70% chamber and the specimen is placed; A parallel beam X-ray irradiator for irradiating X-rays to the specimen in the chamber; And a detection device that detects X-rays that transmit or reflect or diffract the specimen in the chamber. It provides an X-ray analysis apparatus configured to include.
  • the present invention is an X-ray analysis method for graphene having an extremely fine thickness, "(a) preparing an X-ray analysis device of any one of claims 21 to 26; (b) placing the graphene specimen having a layer number of 1 to 10 layers and a size of 0.3 ⁇ 0.3 cm or more in the chamber; And (c) detecting and analyzing X-rays transmitted or diffracted or reflected by the detection apparatus by irradiating X-rays on the graphene specimen with the parallel beam X-ray irradiation apparatus.
  • X-ray analysis method for graphene having an extremely fine thickness comprising a.
  • the graphene of the present invention is graphene made by CVD, and graphene oxide or modiphy graphene physically, mechanically, electrochemically and chemically modified, graphene physically, chemically and mechanically separated from graphite, graphite Thermally reducing chemically oxidized graphite oxide (a type of graphene) or graphene oxide, graphene oxide or graphene oxide thermally reduced, and chemically oxidized graphene, expanded graphene (intercalated carbon compound) Or graphene nanoplates prepared from microwaves or expanded materials due to energy application, graphene exfoliated graphite using physicochemical or solvent, graphene manufactured in top-down format, graphene synthesized from bottom-up On the surface of graphene and SiC produced through decomposition of graphene and hydrocarbons Formed graphene, graphene encapsulated on the surface of the nanoparticles, RGO, graphene nanoplates physically, chemically and electrically modified, such as graphene nanoplates.
  • the graphene surface is known that the oxygen is unconditionally present
  • the graphene of the present invention is characterized in that the oxygen content of 5% or less, sulfur and phosphorus components may be contained less than 5% through the chemical oxidation of graphite. have.
  • the graphene of the present invention may be doped with elements such as boron, phosphorus, sulfur, nitrogen, fluorine through the conventional doping process.
  • the graphene of the present invention may have various groups on the graphene surface through the additional chemical reaction or surface treatment or post-treatment process, it is possible to cut the substituted substituents.
  • the graphene materials of the present invention may be further added in various forms, the criterion of the present invention is the surface oxidizer, functional group, functional group, degree of defects in the basal plane, modified functional group, doping element, oxygen and sulfur content, etc. Regardless of the basal plan on floors 1-10.
  • crystallographic information may be obtained through X-ray analysis and X-ray diffraction analysis of an extreme thin graphene having a thickness of 3 nm or less or 1-10 layers which could not be conventionally performed.
  • the physical property analysis becomes possible, industrial applications of graphene, which is emerging as a next-generation new material, are also possible.
  • the X-ray analysis information can be used as a reference to determine crystallographic information and layer number information of the unknown graphene.
  • the basic specifications of graphene materials (such as the number of layers or thicknesses), which have not been cleared up until now, become clear, and based on this, it is possible to greatly enhance the diversity and certainty of graphene products, securing reliability of finished products and product competitiveness.
  • FIG. 1 is a schematic diagram of an X-ray analyzing apparatus provided by the present invention.
  • FIGS. 2 and 3 are schematic diagrams of another X-ray analyzer.
  • FIG. 4 is a schematic diagram showing that the X-ray irradiation angle of the ultra-thin graphene on the X-ray non-transmissive substrate and the X-rays diffracted therefrom are located in the semisphere of the upper layer of the specimen.
  • FIG. 5 is a schematic diagram showing the X-ray irradiation angle of the ultra-thin graphene on the transmissive substrate and the positions of X-rays transmitted or diffracted by the beams are located in the semispheres of the lower layer of the specimen.
  • FIG. 6 shows the X-ray irradiation angle of the ultra-thin graphene on the transmissive substrate and the position of the X-rays transmitted or diffracted from the X-rays of the upper and lower hemispheres of the specimen, that is, the three-dimensional sphere (Sphere) It is a schematic diagram showing that all rotated X-rays are located at.
  • FIG. 7 is a schematic diagram of a method of manufacturing an X-ray transmissive graphene or X-ray non-transmissive graphene specimen.
  • FIG. 8 is a schematic diagram of a method for fixing and processing graphene specimens.
  • FIG. 9 is an XRD pattern graph of a sample obtained by laminating a single layer graphene thin film from one layer to ten layers by using a transfer method (in order to improve the flatness, a silicon oxide film was formed on a 1 cm ⁇ 1 cm silicon substrate and S1 to S10 are the names of each sample).
  • FIG. 10 is a table of data values obtained by analyzing the (002) peak in FIG. 9.
  • FIG. 11 is a value showing an absolute graphene layer number determined for S1 to S10 samples by analyzing the data of FIG. 10.
  • FIG. 12 is a graph comparing the values of FIG. 11 with theoretical values.
  • FIG. 13 is a graph showing (hkl) peaks of 7-layer graphene found using the GI SAXS method.
  • FIG. 15 is a schematic diagram of the axis of rotation of the specimen in three axes.
  • FIG. 16 is a schematic diagram of a centrifugal rotation of a parallel beam X-ray irradiation apparatus and a detection apparatus in a longitudinal direction and a lateral direction.
  • the present invention is a chamber that is controlled under a temperature condition of 278 ⁇ 328 ° K and a humidity condition of less than 70% and the specimen is placed; A parallel beam X-ray irradiation apparatus for irradiating X-rays to the specimen in the chamber; And a detection device that detects X-rays that transmit or reflect or diffract the specimen in the chamber. It provides an X-ray analysis apparatus configured to include. Details of the temperature and humidity conditions of the chamber will be described later.
  • FIG. 15 is a schematic diagram of the axis of rotation of the specimen in three axes.
  • FIG. 16 is a schematic diagram of a centrifugal rotation of a parallel beam X-ray irradiation apparatus and a detection apparatus in a longitudinal direction and a lateral direction.
  • FIG. 1 is a schematic diagram of an X-ray analyzing apparatus provided by the present invention.
  • the embodiment shown in FIG. 1 is configured to set the irradiation angle ⁇ by fixing the parallel beam X-ray irradiation apparatus and uniaxially rotating the specimen.
  • Irradiation angle ( ⁇ ) means the angle between the irradiated X-ray and the specimen.
  • the 2 ⁇ - ⁇ method is a method of fixing a parallel beam X-ray irradiation apparatus and moving the detection device according to the uniaxial rotational angle of the specimen, and fixing the detection device and moving the parallel beam X-ray irradiation apparatus according to the uniaxial rotational angle of the specimen. Method and the like.
  • the X-ray irradiation angle ⁇ may be set to a very small angle, and then the detector may be rotated at an angle of 2 ⁇ with respect to the X-ray radiated.
  • This method is a GI (Grazing incident) method
  • GI-SAXS method also corresponds to this.
  • the detector in order to reduce the influence of the strong peak of the substrate, the detector is fixed at the position where the peak of the graphene (hkl) crystal plane (mainly (002) peak) comes out and the X-ray irradiation angle ( There is also a method of changing ⁇ ).
  • the specimen can be set by the three-axis rotation angle ( ⁇ (psi) and ⁇ (pie) in Fig. 1). According to the 3-axis rotation angle setting of the specimen, it is possible to secure the X-ray irradiation angle and the detector angle with respect to the partial space on the upper portion of the specimen. This allows partial detection of diffracted X-rays present in the upper layer of the specimen.
  • a specimen without a substrate may be applied.
  • the removed graphene specimen using an etching technique, in which case the specimen may be damaged.
  • the problem can be solved by maximally moving the specimen and maximizing the degree of freedom of X-ray irradiation angle and the angle of the detection device.
  • the X-ray irradiation angle, the arrangement (angle) of the specimen, and the arrangement (angle) of the detection device are important in a three-dimensional crystal structure or a specific crystal plane (for example, the (002) plane) for the ultra-thin graphene specimen. This is because it is necessary to overcome the limitations of existing device technologies in order to analyze the three-dimensional peak shape or the difference between the upper and lower crystal planes in the symmetric crystal structure.
  • the positions of the X-rays diffracted according to the X-ray irradiation angle are all located in the semisphere on the upper part of the specimen as shown in FIG. (Except for the lower hemisphere of the specimen). Therefore, when the specimen is axially rotated in three axes (x, y, z), and the parallel beam X-ray irradiation apparatus and the detection apparatus can be centrifugally rotated in the longitudinal and transverse directions, X-ray detection at all positions is facilitated.
  • the position of the transmitted X-ray or the transmitted and diffracted X-ray is shown in FIG. 5.
  • the specimen is axially rotated in three axes (x, y, z), and the parallel beam X-ray irradiator and detector can be centrifugally rotated in the longitudinal and transverse directions to facilitate the detection of X-rays at all positions. .
  • the graphene film when the graphene film is formed or disposed on the X-ray transflective substrate, part of the X-ray is transmitted and part is reflected (diffraction), so that all spaces of the upper and lower portions of the specimen, that is, three-dimensional, as shown in FIG.
  • the diffracted X-rays can be located in the sphere.
  • the specimen is axially rotated in three axes (x, y, z), and the parallel beam X-ray irradiator and detector can be centrifugally rotated in the longitudinal and transverse directions to facilitate the detection of X-rays at all positions. .
  • the material, thickness and transmittance of the substrate should be checked.
  • a plastic substrate, a ceramic substrate, a porous substrate, a fiber composite substrate, and the like can be selected, and the application can be applied after confirming the transmittance according to the substrate thickness.
  • Various methods of preparing graphene specimens using the X-ray transmissive substrate are shown in FIG. 7.
  • X-ray analysis apparatus provided by the present invention may be provided with a heat treatment device for applying heat to the specimen in the chamber.
  • a humidifier for applying moisture to the specimen in the chamber may be provided together. Details of the heat treatment apparatus and the humidifier will be described later.
  • the present invention provides a method for preparing an X-ray analyzer; (b) placing the graphene specimen having a layer number of 1 to 10 layers and a size of 0.3 ⁇ 0.3 cm or more in the chamber; And (c) detecting and analyzing X-rays transmitted or diffracted or reflected by the detection apparatus by irradiating X-rays on the graphene specimen with the parallel beam X-ray irradiation apparatus.
  • step (c) it is possible to analyze the X-ray diffracted by the Bragg law.
  • the method of analyzing direct transmission X-rays, absorbed X-ray elastic scattering, and inelastic scattering, which are not diffracted by Bragg's law is also applicable.
  • X-rays may be irradiated onto graphene at a certain irradiation angle (ie, the vertical direction of the graphene specimen plane) that does not conform to Bragg's law, and the detector may be positioned on the opposite side to analyze the X-rays that pass through directly.
  • the graphene specimens S3 to S6 (the numbers represent the number of layers of graphene) showed X-ray absorption of 0.5-1% per layer of graphene, which is not based on diffraction factor alone, but X-ray absorption per graphene layer. This shows the physical properties. Further research is needed for each survey angle and number of floors.
  • step (b) it can be placed a variety of graphene specimens.
  • FIG. 7 schematically shows a method for preparing graphene specimens using CVD graphene.
  • a substrate A type
  • a specimen completely removed from the substrate B type
  • a B type specimen transferred to another substrate (C type) using a substrate etching technique.
  • a specimen (D type) manufactured by performing additional partial etching or complete etching on the transfer substrate may be used.
  • Porous substrates, etched substrates, mesh substrates, etc. may be used to increase the X-ray transmittance of C-type specimens.
  • FIG. 7 schematically illustrates a test piece manufacturing method using graphene powder or dispersed graphene.
  • the powder itself is pressed (to maintain the film form by the interfacial bonding force), the specimen (E type), and the graphene powder is pressed or coated on the X-ray transmissive or non-transmissive substrate (F type)
  • a specimen (G type) obtained by pressing or coating a powder on a mesh substrate, a porous substrate, an etched substrate, or the like can be obtained, and a specimen (H type) etched with respect to the substrate of these specimens can be prepared.
  • the graphene powders used here are graphene doped with less than 5% oxygen, heat-reduced graphene, chemically-reduced graphene, graphene oxides (surface oxidizers and modified substituents), ball milling products of graphite, high graphite Energy ball milling products, chemically reactive ball milling (ball milling + chemical reactions (liquid and gas phase), ball milling + carbon dioxide reactions, etc.), graphene nanoplates prepared from expanded graphite.
  • Graphene or graphene oxide containing an oxidizer may be heat treated separately so that the instant of change of the graphene (002) crystal plane is best observed.
  • Graphene specimens can be fixed to the specimen holder, and can be applied by physical methods (compression, pressing, etc.), mechanical methods (screws, etc.), chemical methods (adhesives, pastes, etc.), electromagnetic methods (electrostatic forces, electrostatic films, etc.). It can be settled and fixed by van der Waals force or magnetic force.
  • X-ray analysis apparatus may be provided with a heat treatment device for applying heat to the graphene specimen in the chamber. After coating the liquid graphene dispersion on the substrate, it is possible to remove excess solvent or adsorbed solvent while lightly heat-treated with the heat treatment apparatus. In addition, even when suspected of moisture adsorption on the graphene specimen or to prevent moisture adsorption can be heated in a stable temperature range through the heat treatment apparatus.
  • the specimen holder may be provided with a fixed portion (fastening type, etc.) to hold and secure the graphene specimen as shown in (c) of FIG. 8 in two or four directions on the edge of the graphene specimen, two directions Alternatively, the four-way fixing part may be configured such that two opposite parts behave in pairs. That is, while holding and fixing the graphene specimen may be provided with a micro-stretching device to open the pair of fixing parts facing each other in micro units.
  • the micro-stretching device can be embodied as a device that can be pulled out step by step using an ultra-fine mechanical device and a device that can be pulled out using a piezo material.
  • a CVD 5-layer graphene specimen transferred to a PET film was placed on a metal plate, and a PET film protective film was placed on some upper portions of both sides of the specimen (on the upper side of the graphene). .
  • one side was stretched by about 5% (PET + graphene) X-ray diffraction, and the interlayer spacing was increased by about 3 to 8% after stretching, which is explained by the poor quality of the graphene crystals due to stretching. can do.
  • Samples S1 to S10 shown in FIG. 9 are specimens made by transferring single layer graphene and laminating them from one layer to ten layers. In order to improve the flatness of the graphene crystals, silicon oxide films were formed on a 1 cm x 1 cm silicon substrate and graphene was transferred thereon. The sample names were named S1 to S10, respectively, according to the number of stacked layers.
  • Graphenes physically stacked (Layer by layer lamination) in S1 to S10 samples do not form graphene crystals with the same number of layers.
  • the number of graphene layers physically stacked one by one may be the same as or different from the number of layers actually forming crystals (the number of layers and the number of layers differs when there is a spatially floating state without forming crystals). .
  • the graphene layer number measuring method proposed in the present invention is also necessary in this respect.
  • FIG. 9 is an X-ray diffraction analysis result of a crystal according to the thickness of graphene, which is one of the world's first extreme thin films. This not only studies their physical properties but also provides absolute physical quantities for each graphene layer, suggesting a method that can be used as a reference anywhere in the world.
  • parallel beam optics 2theta-omega mode, rocking curve measurement method, fixed angle incident beam method, GI SAXS method, and the like are used.
  • a parallel beam X-ray mirror was used in the present invention.
  • the peak of the substrate silicon is so strong that a very small amount of graphene (002) peak can be buried. Therefore, in order to obtain only the graphene (002) peak, a near value of 1/2 of 2 ⁇ where the graphene (002) peak is present may be fixed to the incident angle.
  • the rocking curve of the crystal surface of the graphene 002 may be determined first by determining the 2 ⁇ / 2 or near values according to the inclination degree of the graphene crystal surface.
  • the irradiation angle available at this time is possible within the angle range of (2 ⁇ ⁇ 2) ⁇ 1 ° of the graphene (002) peak position 2 ⁇ .
  • the device is configured to allow centrifugal rotation in the longitudinal and transverse directions.
  • the multilayer graphene (002) peaks were subjected to peak fitting using a Gaussian function ('G function') and a Lorentzian function ('L function'). Provided.
  • a Gaussian function 'G function'
  • a Lorentzian function 'L function'
  • any function or program capable of satisfying the X-ray diffraction peaks may be used.
  • the FWHM and the peak center of the XRD peak of the same sample are constant eigenvalues regardless of the same time, place, and XRD apparatus, and some errors may occur due to the noise level and the peak fitting function.
  • FIG. 9 is a graph showing XRD measurement data for S1 to S10. This measurement data does not mean the number of layers corresponding to each of S1 to S10.
  • XRD measurement X-rays in which Cu K ⁇ 1 (1.540598 ⁇ ) and K ⁇ 2 (1.544426) lines were mixed at an intensity ratio of 2: 1 were used. 2 ⁇ was uniformly set to 20-50 ° and step size was 0.016 °, and 2theta (Theta) ) - ⁇ (omega) method.
  • Parallel beam X-ray optics irradiator and Array type detector were separately attached to the X-ray diffraction equipment.
  • parallel beam X-ray mirror optics were separately provided and used.
  • (A) of FIG. 9 is a graph comparing two samples of S1 and S2, and the two graphs are almost identical and no peak shape was found except for the background scattering intensity. Although the peak is not observed despite the measurement for 30 to 50 minutes in one measurement, the result shows that the (002) peak is not formed like graphite (three layers of the basic crystal structure).
  • FIG. 10 shows FWHM values, 2 ⁇ values of peak centers, and d 002 values obtained from 2 ⁇ for S3 to S10 samples using G and L functions.
  • FWHM data related to graphene thickness, or graphene layer number are independent from S3 ⁇ S4 ⁇ S5 and are decreasing with some rules.
  • the FWHM value of the S6 sample is almost identical to the S5 sample.
  • the FWHM values of the S7, S8, and S9 samples also had almost identical values, and the S10 samples independently had the smallest FWHM values. This information is very important.
  • graphene crystals like graphite, are found to have a slight initial (002) peak (FWHM: 4.663-5.06 °) in the S3 sample (S1 and S2 are not observed).
  • the thinnest graphene crystal layer minimum number of layers that can be measured by XRD, like crystals of graphite, is three layers.
  • the S5 sample is very strong and very sharp (FWHM: 1.798-1.84 °) peaks, unlike the S4 sample, which is certainly information about graphene whose main crystal is 5 layers (6 layers is impossible in the lamination process). .
  • the FWHM value of the S6 sample closely matches that of the S5 sample FWHM, reflecting that the stacking process of S6 is only as effective as S5, i.e., the S6 sample shows information about the 5-layer graphene crystal.
  • Samples S7 to S9 have similar values, and are independent of five-layer graphene but have similar trends as the theoretical model, resulting in a smaller FWHM, reflecting six-layer graphene.
  • the S10 sample shows the strongest peak intensity and the peak intensity reduced by about one step compared to the six-layer graphene, which is information on the seven graphene layers.
  • FIG. 11 is a table summarizing the values available on the x-axis to draw a calibration curve.
  • the x-axis may be graphene layer (N L ), and graphene thickness (D) or graphene thickness It can also be set as the inverse (1 / D) of.
  • the graphene thickness (D) may be obtained from the thickness of the graphene film to be analyzed (D 1 ) based on the distance between atomic centers or the thickness of the graphene film to be analyzed (D 2 ) based on the maximum outer distance of atoms. have.
  • Red circles (denoted ⁇ ) reflect the L function fitting results and blue triangle dotted ( ⁇ ) reflect the G function fitting results.
  • the graph (d) of FIG. 12 compares the data obtained by using the x-axis as 1 / D and the y-axis as FWHM (graph corresponding to (c) in FIG. 12) and the graph theoretically obtained by the sherrer equation. Data. Theoretically, the larger the crystal, the more complete the graph becomes toward the origin. On the other hand, in case of experimental values, 3 and 4 graphene layers show a tendency to deviate from the straight line. This is very important data showing that 3 to 4 layers of graphene, which are two-dimensional crystals, have different physical properties from general crystals.
  • degree (°) values of FWHM on the y-axis can be transformed into radian, etc. as appropriate.
  • the size of the nano thin film and the nano grains can be obtained within the slope including the error range of these calibration lines (see FIGS. 10 and 11) and the y-intercepts obtained at this time. That is, when a straight calibration curve is drawn based on the number of graphene layers 5, 6, and 7, the slope is about 14-40, and the y-intercept is -2-2. If an error range is drawn based on the number of floors 3, 4, and 5, the slope and intercept are completely different from the above values.
  • the FWHM errors of the S3 to S7 samples were measured to ⁇ 1.5 °, 1.0 °, 0.5 °, 0.4 °, and 0.4 °, respectively, from the measurement and fitting results of the additional samples.
  • the slope was 14 to 30 and the y-intercept was -2 to 2.
  • the slope and intercept of the maximum possible area were determined under the assumption that the graphene was the straight line for the entire 3 ⁇ 7 layers of graphene.
  • the slope has a region of 12 to 82 and the y-intercept has a region of 1.12 to -4.6.
  • the present study shows the absolute FWHM by the number of graphene layers in [FIG. 12].
  • the number of graphene layers may be determined by comparative analysis with these data.
  • the value of FWHM for the XRD (002) peak obtained after growing the multilayer film graphene crystal is 2.5 °
  • the value of the graphene is 4 layers (3.207 °) and 5 layers (1.844). Since it is half of the value, it is concluded that it is 4.5 stories.
  • there is no graphene crystal of 4.5 layers but it provides very important information that the average value of crystals having multiple layers is 4.5 layers. To date, no such method has been provided.
  • the peaks from the (002) peak fitting can be separated and the half value width of the separated peaks evaluated (compared to the present invention) to determine the graphene layer number distribution. For example, after separating the overlapping multiple peaks without performing a single peak fitting on the sample, providing the number of layers information for each FWHM, and then deciding the crystal quantity for each layer as a fitting peak area, The third layer can be represented as 30%, the fourth layer as 40%, and the fifth layer as 30%. What can be done in this way is another effect of this invention.
  • the angle of rotation of the parallel beam X-ray source, detector, and specimen of the present invention may be all rotatable in the x, y, and z axes. All of these rotations are possible with current technology, but they must be replenished when analyzing extreme thin films.
  • Information on the third to seventh layers in FIG. 9 is a graph when (1) the parallel beam X-ray irradiator and (2) the array type detector are simultaneously operated in the X-ray diffraction apparatus.
  • the (002) peak intensity of the S3 to S5 sensitive samples was set to 100 and compared with changing device technology and measurement conditions. As shown in [Table 1], when the measurement temperature is 5 to 55 ° C (278 to 328 ° K) for the above two device technologies, even the sensitive graphene shows little change in peak intensity (exactly expressed). The range of 5 ⁇ 8 °C and 45 ⁇ 50 °C shows about 2% change, so it is preferable to use 8 ⁇ 45 °C for the rigorous experiment, but there is no big problem in using the temperature range in the normal experiment. ).
  • the peak disappears or shows a sharp decrease, which is very important data showing that the ultra-thin graphene may change during long time measurement.
  • the humidity is 70% or more
  • the (002) peak of the ultra-thin graphene disappears or shows a sharp decrease.
  • Such temperature changes mechanical heat, hot weather conditions
  • humidity ranges are a common condition in conventional X-ray diffraction experiments. If (002) peaks are not obtained or become very weak, misinterpretation may occur. This is not the case in conventional specimens and is the first to be found in very thin graphene.
  • the use of a parallel beam X-ray beam is essential when the number of layers of graphene ultra thin films is 1 to 10, and the array type detector functions to increase the reliability of the measurement.
  • the temperature must be 5 ⁇ 45 °C (278 ⁇ 328 ° K) and less than 70% humidity as the measurement conditions.
  • This peak cannot be found by conventional methods. This is because it is not a crystal plane provided on the thin film vertical plane. In addition to the crystal vertical plane, various peaks exist on the crystal horizontal plane xy plane, and the GI SAXS method is required to find them. In the present invention, a peak other than the (002) crystal plane of the seven-layer graphene was found using this method.
  • the (hkl) index has not yet been determined, the principle of the present invention can be applied to this peak as it is (see d (hkl) and FWHM theory).
  • the GI SAXS method will find another (hkl) facet, but it takes a long time.
  • the GI SAXS with the latest two-dimensional detector that is, the 2D GI SAXS device, it is possible to find the peaks of the graphene xy crystal plane in a short time, and to obtain more information about the determination information (decision coefficient) and thickness information for each graphene layer number. Accurate information can be obtained.
  • the GI SAXS method is powerful enough to find another peak that is much weaker than the graphene (002) peak. Therefore, in the present invention, the GI SAXS method may be important when finding the (002) plane of graphene. Further, 2D GISAXS with a two-dimensional detector can more easily omit graphene peaks. This principle of the present invention is also applicable to the concept of a three-dimensional (or 2.5-dimensional: partial space cover) detector to be developed in the future.
  • FIG. 14 is a graph of rocking curves for 3 to 10 layer (S3 to S10) graphene crystal surfaces.
  • the x-axis is the angle in omega (°).
  • This locking curve is a very important measuring method that tells the orientation of the crystal plane (hkl) and how much it is tilted.
  • the detector was fixed at an angle derived from the following detection angle derivation equation. After doing this, the X-ray diffraction intensity was measured while slightly changing the omega angle from + to-.
  • the locking curve for the graphene (002) crystal plane is shown in FIG.
  • the central value of the peak becomes 1/2 of the peak 2 ⁇ of the crystal plane of the graphene (002) shown in FIG.
  • the crystal orientation center and distribution of each layer graphene crystal are different (peaks of FIG. 14 are a function of the crystal orientation distribution). Intensity decreases from the center to the edge, indicating the tilt of the crystal plane in the plane (0 °) where the peak center coincides with the xy axis of the crystal. That is, when the x-axis of FIG.
  • the present invention also provides the first XRD information showing that the two-dimensional graphenes by number of layers are not located in a perfect two-dimensional plane, but exist in a slightly clumped form (+, 0,-distribution).
  • the fixed incident angle (2 ⁇ ⁇ 2) ⁇ 1 ° described above can be re-expressed based on the peak center omega of the rocking curve, which can be expressed as omega ⁇ 1 °.
  • extreme analytical thin film devices can be equipped with vacuum heat treatment systems and cooling systems such as liquid nitrogen.
  • vacuum heat treatment systems and cooling systems such as liquid nitrogen.
  • the change behavior of the d 002 graphene interplanar spacing can be observed in the case of 6-layer graphene vacuum treatment. As the temperature increases, the interplanar spacing decreases and increases, which can be interpreted as an increase in the crystal quality due to the annealing effect and an increase in the interplanar spacing due to molecular vibration at higher temperatures.
  • Table 2 also shows the variation of interplanar spacing of extreme graphene films in cooling experiments using liquid nitrogen.
  • the change in the interplanar spacing may be explained by the effect of reducing the thermal vibration energy of the graphene molecules, the association of the absorbed water molecules, and the solid phase change.
  • the preferred size of the specimen in the present invention is preferably at least 0.5 cm ⁇ 0.5 cm (the larger the graphene layer, the smaller the specimen).
  • the present invention shows that the thinnest ultimate thin film can obtain crystallographic information of three-layer graphene only when various device opti- ties are combined, and environmental measurement conditions and the measurement methods are simultaneously combined.
  • the CVD graphene used for the S10 specimen of FIG. 10 was transferred to an 8 mm ⁇ 8 mm (width ⁇ length) empty metal holder, and then placed in the center of the X-ray analyzer, and the X-ray irradiation device was placed on the upper left detector based on the specimen.
  • the decrease in transmittance due to absorption and scattering of the graphene specimen itself was about 1 to 3.5.
  • a Hummers method As a method for producing graphene oxide, a Hummers method, a Brodie method, a Hofman & Frenzel method, a Hamdi method, a Staus method, etc., including a Modified Hummers method, may be used.
  • the Modified Hummers method was used.
  • 50 g of micro graphite powder and 40 g of NaNO 3 were added to a solution of ⁇ 200 mL H 2 SO 4 , and slowly added KMnO 4 to 250 g over 1 hour while cooling. Then add 4-7% H 2 SO 4 5L slowly over 1 hour and H 2 O 2 . After centrifugation, the precipitate was washed with 3% H 2 SO 4 -0.5% H 2 O 2 and distilled water to give a yellowish brown graphene oxide aqueous slurry.
  • the graphene powder or graphene contained in the graphene dispersion is 1-10 layers and the principle of the present invention is applied, only the thickness of the specimen shows that these graphene is simply stacked. Therefore, the present invention means that the number of layers in the CVD graphene is 1 to 10 layers, in the case of graphene powder means that the number of layers in one graphene is 1 to 10 layers.
  • the chemical reduction method is to disperse well by adding 100 ml of distilled water to 2 g of 3% graphene oxide slurry, and then adding 1 ml of hydrazine hydrate and reducing the process at 100 ° C. for 3 to 24 hours. Filter by filter paper and wash with water and methanol. Before treating a strong reducing agent such as hydrazine hydrate, a salt of an alkali metal or an alkaline earth metal such as KI or NaCl may be used to remove H 2 O from graphene oxide in advance to partially restore carbon-to-carbon double bonds. . As a specific experimental example, 6 g of KI was added to a 5% graphene oxide slurry and left for 6 days to complete the reaction.
  • the X-ray irradiation apparatus, the detector, and the specimen should all be able to move in the x-, y-, and z-axes in three-dimensional space (Sphere). This enables analysis of other hidden crystal planes, analysis of low angle transmission and low angle absorption, and mutual comparison of low angle half scattering methods (surface roughness, X-ray absorption, fluorescence analysis, etc.). need).
  • the present invention is limited to X-ray transmission, X-ray absorption, X-ray diffraction by reflection, X-ray diffraction by transmission, diffraction of a specific X-ray crystal plane, Rockin curve of the specific crystal surface, the present invention is limited to the extremely fine thickness It is directly applied to X-ray analysis method of graphene having X-ray diffraction method, X-ray reflection method, X-ray transmission method, X-ray absorption method, X-ray scattering method, X-ray fluorescence method, X-ray imaging method.

Abstract

The present invention relates to a graphene analysis method and, more particularly, to a technique regarding a method for accurately measuring and determining, on the basis of the number of layers, the thickness of graphene having an ultrafine thickness of an atom-molecule-nano unit, and to a method for detecting, on the basis of data obtained therefrom, the thickness (number of layers) of unknown graphene samples, the thickness of nano thin films, and the size (average value, distribution, etc.) of nanocrystal grains, the methods having remained a challenge up to now and being capable of being implemented through only theoretical approaches. The present invention provides a graphene analysis method comprising the steps of: (a) obtaining diffraction peaks (002) by performing an XRD measurement for graphene defined according to the number of layers; and (b) deriving, from the peaks (002) for the number of layers, valid information about the graphene thickness including the full width at half maximum (FWHM) and interlayer spacing (d002).

Description

그래핀 레퍼런스 도출 방법, 이를 이용한 나노박막 분석 방법, X선 분석 장치 및 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법 Graphene reference derivation method, nano thin film analysis method, X-ray analysis device and X-ray analysis method for graphene having extremely fine thickness
본 발명은 현재까지 난제로 남아있고 이론적 접근만 가능하였던 원자-분자-나노단위의 초미세 두께를 갖는 그래핀 두께를 XRD(X-Ray Diffraction) 방법으로 층 수 단위로 정확히 측정하여 유효 데이터를 도출하는 방법과 여기서 얻은 유효 데이터를 기준으로 미지의 그래핀 시료들의 두께(층 수), 미지의 나노박막의 두께, 나노결정립들의 크기(평균치, 분포 등) 등을 알아내는 그래핀 레퍼런스 도출 방법 및 이를 이용한 나노박막 분석 방법에 관한 것이다.The present invention derives the effective data by accurately measuring the graphene thickness having the ultra-fine thickness of atomic-molecular-nano units, which has remained difficult until now, and only theoretically, by the X-ray diffraction (XRD) method. And a graphene reference derivation method for determining the thickness (number of layers) of unknown graphene samples, the thickness of an unknown nano thin film, the size of nanocrystals (average value, distribution, etc.) It relates to a nano thin film analysis method used.
또한, 본 발명은 그동안 미지 영역으로 남아있던 극 미세 박막을 분석하기 위한 X선 분석 장치 및 X선을 이용한 극한 초박막 그래핀(두께 0.35nm~3nm)의 결정학적 분석방법에 관한 것이다.In addition, the present invention relates to an X-ray analyzer for analyzing an ultra-fine thin film remaining in the unknown region and a crystallographic analysis method of the ultra-thin graphene (thickness 0.35nm ~ 3nm) using X-rays.
소재(물질)에 대한 엑스선(X-ray) 분석방법은 매우 중요하다. 대표적인 엑스선 분석방법으로서, 엑스선 산란법, 엑스선 반사법, 엑스선 흡수법, 엑스선 형광법, 엑스선 모르폴로지 및 토폴로지 분석법(이미지화), 엑스선 회절법이 있다. 최근 장비기술의 발전으로 수 nm 두께의 박막 및 수 nm 크기의 나노그레인에 대한 엑스선 분석들이 가능해지고 있다. 그러나 약 3nm 이하의 단결정 막 및 2~3nm이하의 극 미세 두께 및 극한 크기의 나노그레인 분석방법은 현 엑스선 분석 기술로는 매우 힘든 것으로 판단되고 있으며, 이를 극복하는 것이 차세대 기술로드맵이 되고 있다. 이 로드맵은 매우 중요하다. 즉 두께 0.5~3nm 사이의 극한 박막의 분석 을 통하여 이들을 신소재로 응용하는 방안을 연구할 수 있다. 이들의 물성이 원자/분자와 기존 나노소재간 연결고리를 제공하기 때문에(두께 의존성 및 Size effect) 물질 물성 발현의 기원 등에 대한 연구가 가능해진다.X-ray analysis of the material is very important. Representative X-ray analysis methods include X-ray scattering, X-ray reflection, X-ray absorption, X-ray fluorescence, X-ray morphology and topology analysis (imaging), and X-ray diffraction. Recent advances in equipment technology have enabled X-ray analysis of thin films of several nm thickness and nanograins of several nm size. However, single crystal films of less than about 3nm and nanograin analysis methods having extremely small thickness and size of less than 2 ~ 3nm are considered to be very difficult with current X-ray analysis technology, and overcoming them has become a next-generation technology roadmap. This roadmap is very important. In other words, through the analysis of the extreme thin film with a thickness of 0.5 ~ 3nm can be studied how to apply them as a new material. Since their physical properties provide a link between atoms / molecules and existing nanomaterials (thickness dependence and size effect), it is possible to study the origin of material properties.
두께 0.5~3nm 결정막에 대한 엑스선 분석의 어려움은 다음 네가지 이유에 기인한다. The difficulty of X-ray analysis for a 0.5-3 nm thick crystal film is due to the following four reasons.
(1) 시편 제조의 어려움(고도의 제조기술 필요 및 제조된 시편에 대한 저신뢰성/저재현성) (1) Difficulties in the manufacture of specimens (high level of manufacturing techniques and low reliability / reproducibility of the prepared specimens)
(2) 시편의 열역학적 불안정성에 의한 시편 변화 및 오염(산화 등) (2) Specimen change and contamination (oxidation, etc.) due to thermodynamic instability of the specimen
(3) 상기 변화 및 오염의 확인 및 변화정도(오염정도) 파악의 어려움 (3) Difficulty in identifying the change and contamination and grasping the change (pollution degree)
(4) 엑스선 분석 장치의 한계 및 엑스선 분석방법의 부재(4) Limitations of X-ray Analyzer and Absence of X-ray Analysis Method
상기 (1) 이유를 구체적으로 설명하면 다음과 같다. 박막이든 나노입자이든 원자, 분자단위 요소들이 뭉치며 핵이 생성되고(Nucleation), 이 핵들이 충돌 등을 통하여 성장해 나간다. 이때 얻어낼 수 있는 최소 핵의 크기 즉 최소 나노입자의 크기는 3nm 이상이다. 즉 3nm 이하의 나노 입자를 얻어내기는 매우 힘들다. 이것은 더 큰 형태로 성장이 되려는 자발적인 성질 때문이며, 나노입자의 열역학적 안정성은 입자에 크기에 크게 의존한다(이 점은 상기 (2) 이유와도 관계됨).The reason for the above (1) will be described in detail. Whether thin or nanoparticles, atoms and molecules are united in nucleation, and these nuclei grow through collisions. At this time, the minimum nucleus size that can be obtained, that is, the minimum nanoparticle size is more than 3nm. That is, it is very difficult to obtain nanoparticles of 3 nm or less. This is due to the spontaneous nature of growth in larger forms, and the thermodynamic stability of the nanoparticles depends largely on the size of the particles (this is also relevant for reason (2) above).
상기 (2) 이유를 구체적으로 설명하면 다음과 같다. 3nm 이하의 나노입자 혹은 나노박막은 열역학적으로 극도로 불안정하여 적은 열에너지(상온에서도 자발적으로 변하는 시료가 많다) 및 습도에도 반응성이 높아 변화가 일어나거나 전혀 다른 상태로 변해 버린다. 따라서 엑스선 측정 중에도 변화가 일어날 수 있다. 따라서 극한 박막의 경우 고유의 물성을 잃어버려 결과가 나오지 않거나 잘못된 결과가 나오게 된다.The reason for the above (2) will be described in detail. Nanoparticles or nanofilms below 3nm are extremely thermodynamically unstable and are highly reactive with low thermal energy (a lot of samples change spontaneously at room temperature) and humidity, resulting in changes or completely different states. Therefore, a change may occur during X-ray measurement. Therefore, in the case of the extreme thin film, the inherent physical properties are lost and no result or wrong result is obtained.
상기 (3) 이유를 구체적으로 설명하면 다음과 같다. 극한 박막 분석시 변하거나 변하는 정도 또는 오염이 되는 정도의 환경적 요인을 파악하고 이를 레시피화하여 제공되어야 하지만, 극한 박막의 제조부터 분석까지가 너무 어려워서, (1) 환경적 요인(온도 및 습도), (2) 측정 요인(장치구성요소 및 측정방법) 및 (3) 시편 스펙(크기, 두께, 형상 등)을 얻어내는 실험자체가 불가능해진다. 따라서, 시편의 변하는 정도 및 오염정도를 파악하는 실험은 매우 어려워진다.The reason for the above (3) will be described in detail. In the analysis of extreme thin film, environmental factors such as change, change or contamination should be identified and provided. However, it is too difficult to manufacture and analyze extreme thin film, so (1) environmental factors (temperature and humidity) , (2) the measurement factors (device components and measurement methods) and (3) specimen specifications (size, thickness, shape, etc.) cannot be obtained. Therefore, experiments to determine the degree of change and contamination of the specimen become very difficult.
상기 (4) 이유를 구체적으로 설명하면 다음과 같다. 적절한 강도 이상의 X선 빔, X선 조사방법, 검출기 종류, 검출방법, 기판 영향고려 등을 포함한 종합적인 분석 툴이 미미하여 극한 초미세 박막 및 초미세 나노입자의 분석이 극히 어렵다. 일 예로 통상적으로 극한 박막에 대하여 엑스선을 조사할 경우 상층부 타겟 박막에 대한 정보는 전혀 나오지 않고 기판에 대한 정보만 얻어진다. 이는 투과력이 매우 큰 엑스선 빔의 특징으로서 당연한 일이다(신체의 뼈를 측정하는 엑스선 참조).The reason for the above (4) will be described in detail. Comprehensive analysis tools including X-ray beams, X-ray irradiation methods, detector types, detection methods, and substrate influence considerations of adequate intensity are insignificant, making it extremely difficult to analyze extremely thin films and ultra-fine nanoparticles. For example, when X-rays are irradiated with an extreme thin film, only information on the substrate is obtained without any information about the upper target thin film. This is a natural feature of X-ray beams with very high penetration (see X-rays, which measure the body's bones).
극한 박막으로서의 그래핀은 양자역학적 물성이 발현될 수 있는(흑연 및 나노탄소와 구분이 되는 성질) 1~10층(두께 3nm 이하)인 신소재이다. 그래핀은 전기적 물성, 기계적 강도, 열전도성 등이 뛰어나 소재 및 학문적 분야에서 많은 역할을 하고 있다.Graphene as an extreme thin film is a new material having 1 to 10 layers (3 nm or less in thickness) that can exhibit quantum mechanical properties (distinct from graphite and nano carbon). Graphene plays many roles in materials and academic fields because of its excellent electrical properties, mechanical strength, and thermal conductivity.
그래핀은 크게 하이드로카본의 열분해 증착(CVD법)에 의해 만들어진 박막형 그래핀과 흑연의 물리화학적 박리를 통하여 얻어지는 분말형 그래핀 2종으로 구분할 수 있다. 그래핀은 층 수가 하나씩 늘어날 때마다 전자구조 및 양자역학적 물성이 바뀌어 새로운 물성이 발현된다. 따라서 그래핀의 층 수를 알아내고 층수 별로 물성을 연구하는 것은 매우 중요하다.Graphene can be largely classified into two types of thin graphene, which is obtained by pyrolysis deposition (CVD) of hydrocarbon, and powdered graphene obtained through physicochemical exfoliation of graphite. As the number of layers increases, the graphene changes its electronic structure and quantum mechanical properties to express new properties. Therefore, it is very important to find out the number of layers of graphene and to study the properties of each layer.
그러나 10층 이하의 박막 그래핀의 XRD 회절 보고는 거의 없으며 통상적으로 국부적인, 즉 마이크로미터 영역의 라만 분석법 및 전자현미경법을 이용하여 층 수 분석을 하고 있는데 이는 신뢰도가 낮고 롤투롤 대면적 그래핀의 결정성 분석과는 거리가 멀어 그래핀 상용화의 1차 걸림돌이 되고 있다. 즉 빙상의 극히 일부만의 두께를 분석하여 빙상 전체가 안전하다고 판단하는 것이 대단히 큰 오류인 것과 마찬기지로, 약 백만분의 1정도의 데이터를 가지고 전체 그래핀 층 수와 두께를 논하는 것은 매우 심각한 일이고 현실적 대안이 없는 상태이다.However, there are few reports of XRD diffraction of thin film graphene of less than 10 layers and are usually analyzed by local Raman analysis and electron microscopy in the micrometer region, which have low reliability and large roll-to-roll area graphene. It is far from the crystallinity analysis of, making it the first obstacle to commercialization of graphene. In other words, analyzing the thickness of only a small portion of the ice sheet and determining that the entire ice sheet is safe is a very big error. It is very serious to discuss the total graphene layer number and thickness with about one million data. It's work and there's no realistic alternative.
박막형 그래핀의 경우 균일한 1층을 만드는 기술은 상당한 신뢰성을 가지고 있는데 통상적으로 대면적 구리(Cu) 호일 위에 롤투롤(R2R)로 제조된다. 이 단층막 그래핀은 에칭 등을 통하여 구리 호일에서 떼어내는데, PDMS와 같은 폴리머에 붙여 원하는 기판에 옮기는 기술, 즉 전사기술은 매우 발전되어 현재 상용화 전단계까지 와 있다. 그러나 보호막이 없이 그래핀을 공기중에 노출이 될 경우 산화반응(-OH 생성) 및 그래핀 층간 산소 및 수분 침부에 의한 결정 파괴 현상이 일어나는 문제가 발생한다.In the case of thin graphene, the technique of making a uniform single layer is quite reliable and is typically made of roll-to-roll (R2R) on a large area copper (Cu) foil. The single layer graphene is removed from the copper foil through etching, and the technology of transferring it to a desired substrate by attaching it to a polymer such as PDMS, that is, a transfer technology, is very advanced and is now at the stage of commercialization. However, when graphene is exposed to air without a protective film, a problem occurs in that the crystallization phenomenon occurs due to oxidation reaction (-OH production) and immersion of graphene oxygen and moisture.
그러나 현재 2층 이상의 층 수를 갖는 다층막 그래핀을 신뢰성 있게 만들어 내지는 못하고 있는데, 그 이유는 단층막 그래핀 위에 또 다른 탄소원자가 성장될 경우 수평방향 이외에 수직방향으로의 탄소-탄소 결합 자유도가 급속히 커져(엔트로피 증가, 자유도 증가) 층 수 제어가 불가능해지기 때문이다. 즉, 다층막 그래핀막의 제조 메커니즘은 Cu-C 결합을 최대한 유도시키는 단층막 그래핀 제조공정과는 다른 것이다. 이런 이유로 그래핀 층 수 별 물성연구가 미미하며, 당연히 그래핀의 층 수를 측정하는 방법도 개발되어 있지 못하다.However, at present, multilayered graphene having two or more layers has not been made reliably because, when another carbon atom is grown on the single-layered graphene, the degree of freedom of carbon-carbon bonds in the vertical direction other than the horizontal direction is rapidly increased. (Increased entropy, increased degrees of freedom) This is because control of the number of layers becomes impossible. That is, the manufacturing mechanism of the multilayer graphene film is different from the monolayer graphene manufacturing process that induces the Cu-C bond to the maximum. For this reason, there are few studies on the physical properties of graphene layers, and of course, no method of measuring the number of graphene layers has been developed.
한편, 그래핀 분말은 흑연을 박리시켜 제조하기 때문에 통상적으로 다층막으로 이루어져 있지만, 가장자리부분, 가장자리 근처부분, 중심부분 등의 층수가 모두 다르다. 즉 2차원 평면 구조를 갖는 그래핀 분말 1개에서도 층 수 분포가 다른 것이다. 또한 그래핀 분말들 사이의 층 수 분포도 다르다. 물론 분말 전체에 대한 평균적인 그래핀 층 수 또는 층 수 분포를 알 수 있는 측정방법도 개발되어 있지 않다.On the other hand, graphene powder is usually made of a multilayer film because it is produced by peeling graphite, but the number of layers, such as the edge portion, the edge portion, and the center portion, are all different. In other words, even one graphene powder having a two-dimensional planar structure has a different layer number distribution. Also the layer number distribution between the graphene powders is different. Of course, no measurement method for knowing the average graphene layer number or layer number distribution of the entire powder has been developed.
그래핀 층 수 평가(측정)법이 개발되어 있지 않기 때문에 그래핀 제조 및 그래핀 상용화에 큰 걸림돌이 되고 있다. 그래핀 분말을 상용화하기 위해서는 그래핀 분말을 톤 단위로 제조할 수 있어야 하는데, 제조 공정시 최소 1mg(약105개)에 대한 평균 층 수(혹은 두께)를 즉각적으로 알아야 대량 생산 그래핀에 대한 샘플링 테스트를 반복함으로서 1kg(약 1011개), 1ton(약 1014개)에 대한 평균 그래핀 층 수 평가를 할 수 있다. 또한 분석결과로부터 제조공정을 다시 검토해볼 수 있어 대량 그래핀의 층 수 평가법은 산업적으로 매우 중요하다.Since no graphene layer number evaluation (measurement) method has been developed, it is a major obstacle to graphene production and commercialization of graphene. In order to commercialize graphene powder, it is necessary to be able to produce graphene powder in tons. In the manufacturing process, the average number of layers (or thicknesses) for at least 1 mg (about 10 5 pieces) should be immediately known for mass production graphene. By repeating the sampling test, an average graphene layer count for 1 kg (about 10 11 ) and 1 ton (about 10 14 ) can be evaluated. In addition, it is possible to review the manufacturing process from the analysis results, so the method for evaluating the layer number of bulk graphene is very important industrially.
엑스선 회절(X-ray diffraction)은 입사된 엑스선에 대하여 특정결정면에 대한 브래그법칙(Bragg 법칙(Cullity, 1978))을 만족하며 회절 되어 나온 엑스선을 분석하는 방법으로서 아래의 [식 1]로 표현된다.X-ray diffraction is a method of analyzing the X-ray diffracted by satisfying Bragg's law (Cragity law (Cullity, 1978)) for a specific crystal plane with respect to the incident X-rays is represented by the following [Equation 1] .
[식 1] nλ = 2d(hkl)sinθNλ = 2d (hkl) sinθ
여기서 λ는 X-ray 파장, θ는 회절각, n는 정수로 표현되는 회절피크의 차수, d는 격자의 면간거리(간격)이며, (hkl)은 결정면의 밀러지수이다. Where λ is the X-ray wavelength, θ is the diffraction angle, n is the order of diffraction peaks expressed as an integer, d is the interplanar distance (interval) of the grating, and (hkl) is the Miller index of the crystal plane.
Sherrer’s equation(Cullity, 1978)에 의한 결정면의 두께는 아래의 [식 2]로 표현 된다.The thickness of the crystal plane by the Sherrer's equation (Cullity, 1978) is expressed by Equation 2 below.
[식 2] D = Kλ/BcosθD = Kλ / Bcos θ
여기서 D 는 결정면의 두께, K는 결정립의 형태에 의존하는 상수(통상적으로 0.89), λ는 X-ray 파장, B는 FWHM(full width at half maximum; 반가치폭), 그리고 θ는 회절각이다.Where D is a constant of the crystal surface, K is a constant (typically 0.89) depending on the shape of the grain, λ is the X-ray wavelength, B is FWHM (full width at half maximum), and θ is the diffraction angle.
본 발명에서는 절대적 그래핀 층 수에 따른 XRD 피크를 얻어냄으로써 FWHM(full width at half maximum) 및 층간간격을 포함한 그래핀 두께에 대한 유효정보를 도출하는 방법을 제공하고자 한다.The present invention is to provide a method for deriving the effective information on the graphene thickness including the full width at half maximum (FWHM) and the interlayer spacing by obtaining the XRD peak according to the absolute graphene layer number.
XRD 방법으로 그래핀 피크를 측정할 때에는 그래핀 분말은 두껍게 쌓아올려 측정하기 때문에, 그래핀의 대표적 피크인 밀러지수 (002)인 그래핀 결정면의 피크(이하 '그래핀 (002) 피크'라 함)를 손쉽게 얻어낼 수 있지만 층 수 정보는 알 수 없어, 이들을 표준시료로 하여 층 수에 따른 XRD 피크를 얻어내는 것은 거의 불가능하다.When the graphene peak is measured by the XRD method, since the graphene powder is measured by stacking it thickly, the peak of the graphene crystal surface, which is the representative index of graphene (002) (hereinafter referred to as 'graphene (002) peak') ) Can be easily obtained, but the number of layers is unknown, and it is almost impossible to obtain XRD peaks according to the number of layers using these as standard samples.
또한 박막형 그래핀의 경우, 만일 층 수에 따른 완벽한 그래핀 결정을 만든다 해도 두께가 너무 얇아{1층(3.5Å 이하), 2층(~7Å), 3층(~10.5Å), 4층(~14Å), 5층(~17.5Å), 6층(~21Å), 7층(~24.5Å)} 통상적인 XRD 측정 방법으로 피크를 얻어낼 수 없으며 이들에 대한 XRD 연구도 거의 전무한 실정이다.In addition, in the case of thin graphene, even if perfect graphene crystals are made according to the number of layers, the thickness is too thin (1 layer (3.5 kV or less), 2 layer (~ 7 kPa), 3 layer (~ 10.5 kPa), 4 layer ( ~ 14Å), 5 layers (~ 17.5Å), 6 layers (~ 21Å), 7 layers (~ 24.5Å)} Peaks cannot be obtained by conventional XRD measurement methods, and there are almost no XRD studies on these.
따라서 본 발명에서는 그래핀 1~10층으로 추정되는 그래핀 결정들에 대하여 XRD 회절 피크를 얻어내는 방법을 알아낸 후, 이들 XRD 정보를 해석하여 그래핀 층 수 1층, 2층, 3층, 4층, 5층, 6층, 7층을 결정하고(이 과정에서 피팅함수 또는 컴퓨터 프로그램 이용 가능) 이들을 검량선으로 활용하는 방법을 제공하고자 한다.Therefore, in the present invention, after finding a method of obtaining XRD diffraction peaks for graphene crystals estimated to be graphene 1 to 10 layers, the XRD information is analyzed to determine the number of graphene layers 1 layer, 2 layers, 3 layers, We want to provide a way to determine the 4th, 5th, 6th, and 7th floors (fitting functions or computer programs can be used in this process) and use them as calibration curves.
추가로, 그래핀 박막은 단결정 형태로 기판에 성장 또는 적층되기 때문에 기판에 수직인 우선성장된 결정면(Orientated Crysta facet)이 있으면 통상적인 방법으로는 그 결정 피크밖에 얻을 수 없으나, 본 방법은 GI SAXS(Grazing incident small-angle X-ray) 측정법을 이용하여 막 내부에 숨어 있는 또 다른 결정면을 O아 내고자 하였다. 그래핀의 경우는 이에 대한 연구가 전무하다. 따라서 그래핀 박막이 형성된 기판에 수직인 면, 즉 그래핀 (002) 면이 우선적인 결정면이 되면 다른 (hkl) 면은 막 내부에 숨어 있게 된다. 그래핀 (002) 결정면 이외의 다른 면에서의 회절 피크는 그래핀 단위 격자에 대한 정보를 제공해준다. 따라서 본 발명에서는 XRD 방법을 통해 층 수별 그래핀 (002) 피크를 얻어내는 방법과 및 이를 통해 그래핀 두께를 측정하는 방법 그리고 기타 그래핀 (hkl) 피크를 얻어내는 방법 등에 따른 그래핀 레퍼런스 도출 방법 및 이를 이용한 나노박막 분석 방법을 제공하고자 한다.In addition, since the graphene thin film is grown or stacked on the substrate in the form of a single crystal, if there is an orientated Crysta facet perpendicular to the substrate, only the crystal peak can be obtained by the conventional method. Grazing incident small-angle X-ray method was used to omit another crystalline surface hidden inside the membrane. In the case of graphene, there is no research on this. Therefore, when the surface perpendicular to the substrate on which the graphene thin film is formed, that is, the graphene (002) surface becomes a preferential crystal surface, the other (hkl) surface is hidden inside the film. Diffraction peaks on surfaces other than the graphene (002) crystal plane provide information about the graphene unit lattice. Therefore, in the present invention, a graphene reference derivation method according to a method of obtaining graphene (002) peaks per layer number through XRD method, a graphene thickness measurement method, and a method of obtaining other graphene (hkl) peaks through this method And to provide a nano thin film analysis method using the same.
또한, 본 발명에서는 두께 3nm 이하, 구체적으로는 3.5Å에서 2.5nm까지 두께가 차별화된 그래핀 결정 7종에 대하여 다양한 엑스선 소스 및 검출 장치 및 측정방법을 적용하여 두께별 (002) 결정면 하나의 피크라도 얻어내고자 하였다.In addition, in the present invention, a peak of one (002) crystal plane for each thickness is applied by applying various X-ray sources, detection apparatuses, and measurement methods to seven types of graphene crystals having a thickness of 3 nm or less, specifically, 3.5 Å to 2.5 nm. To obtain the rado.
또한, 본 발명에서는 두께별 극한 박막 그래핀의 (002) 결정면으로부터 극한 박막 결정들의 중요한 결정학적 정보를 얻어내는 방법을 제공하고자 한다.In addition, the present invention is to provide a method for obtaining important crystallographic information of the extreme thin film crystals from the (002) crystal surface of the extreme thin film graphene by thickness.
또한, 극한 그래핀 박막의 표면이 산화되지 않으면서도 2층 이상 그래핀 결정의 층간 간격이 변하지 않는 안정적인 환경 조건(온도, 습도)을 찾아내어 분석하는 방법을 제공하고자 한다.In addition, it is to provide a method for finding and analyzing stable environmental conditions (temperature, humidity) in which the interlayer spacing of two or more layers of graphene crystals does not change even though the surface of the extreme graphene thin film is not oxidized.
본 발명은 「(a) 층 수 별로 정의된 기준 그래핀을 준비하는 단계; (b) 상기 기준 그래핀에 대하여 XRD 측정을 수행하여 특정 밀러지수를 갖는 그래핀 결정면의 회절 피크를 얻어내는 단계; 및 (c) 상기 밀러지수를 갖는 그래핀 결정면의 회절 피크들로부터 FWHM(full width at half maximum) 및 층간간격을 포함한 그래핀 두께에 대한 유효정보를 도출하는 단계; 를 포함하는 그래핀 레퍼런스 도출방법」을 제공한다.The present invention is a step of (a) preparing a reference graphene defined by the number of layers; (b) performing XRD measurements on the reference graphene to obtain diffraction peaks of the graphene crystal plane having a specific Miller index; And (c) deriving valid information on the graphene thickness including full width at half maximum (FWHM) and interlayer spacing from diffraction peaks of the graphene crystal plane having the Miller index. It provides a graphene reference derivation method comprising a.
상기 (a)단계에서는 단층 그래핀을 적층하여 층 수 별로 정의된 기준 그래핀을 수득하도록 할 수 있다.In the step (a) it is possible to obtain a reference graphene defined by the number of layers by stacking single layer graphene.
상기 (b)단계에서는 상기 기준 그래핀에 대한 XRD 측정시, X선 조사각 설정 전에 특정 밀러지수를 갖는 결정면의 록킹커브(rocking curve)를 우선 측정하여 배향성을 확인토록 할 수 있다. 이 경우 X선 조사각을 하기 [조사각 도출식]에 따라 도출된 각도범위 내에서 설정할 수 있다.In the step (b), when the XRD of the reference graphene is measured, the rocking curve of the crystal plane having a specific Miller index may be first determined before setting the X-ray irradiation angle to check the orientation. In this case, the X-ray irradiation angle may be set within the angle range derived according to the following [Emission Angle Derivation Formula].
[조사각 도출식][Derivation angle of expression]
X선 조사각 = (2θ(hkl)÷2)±1˚X-ray irradiation angle = (2θ (hkl) ÷ 2) ± 1˚
2θ(hkl) : 특정 밀러지수를 갖는 기준 그래핀 결정면 피크 센터의 각도2θ (hkl): angle of peak center of reference graphene crystal face with specific Miller index
또한, 상기 (b)단계에서는 상기 기준 그래핀에 대한 XRD 측정시 GI SAXS 측정방법을 수행하여, 밀러지수가 (002)인 결정면을 제외한 나머지 결정면의 회절 피크를 얻도록 할 수 있다. 이 경우 평행빔 X선 광학기(Parallel beam X-ray optics)를 이용하여 상기 기준 그래핀에 대한 XRD 측정을 수행할 수 있으며, 상기 XRD 측정은 2theta(쎄타)-ω(오메가) 모드로 수행할 수 있다.In addition, in step (b), a GI SAXS measuring method may be performed when XRD of the reference graphene is measured, thereby obtaining diffraction peaks of the remaining crystal surfaces except for the crystal surface with Miller index (002). In this case, parallel beam X-ray optics may be used to perform XRD measurement on the reference graphene, and the XRD measurement may be performed in 2theta (theta) -ω (omega) mode. Can be.
또한, 상기 (b)단계에서는 상기 기준 그래핀에 대한 XRD 측정시 밀러지수가 (002)인 결정면의 회절 피크를 얻어내도록 할 수 있는데, 이 경우에도 평행빔 X선 광학기(Parallel beam X-ray optics)를 이용하여 상기 기준 그래핀에 대한 XRD 측정을 수행할 수 있으며, 상기 XRD 측정은 2theta(쎄타)-ω(오메가) 모드로 수행할 수 있다. 이 후 상기 (c)단계에서는 가우시안 함수(Gaussian Function) 또는 로렌찌안 함수(Lorentian Function)를 이용하여 상기 기준 그래핀의 층 수 별 피크에 대한 피크 피팅을 수행하여 상기 유효정보를 도출할 수 있다.Further, in the step (b), the diffraction peak of the crystal plane with the Miller index (002) can be obtained when XRD is measured with respect to the reference graphene. In this case, parallel beam X-ray optics (Parallel beam X-ray) optics) can be used to perform XRD measurements on the reference graphene, and the XRD measurement can be performed in 2theta (theta) -ω (omega) mode. Thereafter, in the step (c), the effective information may be derived by performing a peak fitting on the peaks of the number of layers of the reference graphene using a Gaussian function or a Lorentian function.
이 때, X선 조사각 설정 전에는 밀러지수 (002)를 갖는 그래핀 결정면의 록킹커브(rocking curve)를 우선 측정하여 배향성을 확인하고, 상기 X선 조사각을 하기 [조사각 도출식]에 따라 도출된 각도범위 내에서 설정할 수 있다.At this time, before setting the X-ray irradiation angle, the rocking curve of the graphene crystal surface having the Miller index (002) is first measured to confirm the orientation, and the X-ray irradiation angle is determined according to the following [Emission Angle Derivation Formula]. It can be set within the derived angle range.
[조사각 도출식][Derivation angle of expression]
X선 조사각 = (2θ(002)÷2)±1˚X-ray irradiation angle = (2θ (002) ÷ 2) ± 1˚
2θ(002) : 밀러지수가 (002)인 기준 그래핀 결정면의 피크 센터의 회절각2θ (002): diffraction angle of the peak center of the reference graphene crystal plane with Miller index (002)
상기 (c)단계에서는 하기 [층간간격 도출식]에 의해 기준 그래핀의 층간간격(d002)을 도출할 수 있다.In the step (c) it is possible to derive the interlayer spacing (d002) of the reference graphene by the following [interlayer spacing derivation formula].
[층간간격 도출식][Interval of Floor Interval]
d(002) = nλ/2sinθ(002) d (002) = nλ / 2sinθ (002)
d002 : 결정면의 밀러지수가 (002)인 기준 그래핀의 층간간격d 002 : Interlayer spacing of reference graphene with Miller index of crystal plane (002)
λ : X-ray 파장λ: X-ray wavelength
2θ(002) : 밀러지수가 (002)인 기준 그래핀 결정면의 피크 센터의 회절각2θ (002) : diffraction angle of the peak center of the reference graphene crystal plane with Miller index (002)
n : 정수로 표현되는 회절피크의 차수n: degree of diffraction peak expressed as an integer
전술한 바와 같이 기준 그래핀으로부터 FWHM(full width at half maximum) 및 층간간격을 포함한 유효정보를 도출한 후, 본 발명은 상기 유효정보에 기초하여 검량선을 작성하는 단계((d)단계) 를 더 포함하는 그래핀 레퍼런스 도출방법을 함께 제공한다.After deriving the valid information including the full width at half maximum (FWHM) and the interlayer spacing from the reference graphene as described above, the present invention further comprises the step (d) of creating a calibration curve based on the valid information. A graphene reference derivation method is included.
또한, 본 발명은 「(A) 분석대상 나노박막에 대하여 XRD 측정을 수행하는 단계; 및 (B) 상기 XRD 측정 결과를 상기 그래핀 레퍼런스 도출 방법에 따라 작성된 검량선과 대비하여 상기 분석대상 나노박막의 두께를 포함하는 데이터를 측정하는 단계; 를 더 포함하는 것을 특징으로 하는 나노박막 분석 방법」을 함께 제공한다.In addition, the present invention "(A) performing the XRD measurement on the nano thin film to be analyzed; And (B) measuring data including the thickness of the analyte nano thin film by comparing the XRD measurement result with a calibration curve prepared according to the graphene reference derivation method; It provides together with the "nano thin film analysis method characterized in that it further comprises.
이 때 상기 (A)단계의 분석대상 나노박막으로서 그래핀막을 선정하는 경우, 상기 (B)단계의 데이터는 분석대상 그래핀막의 그래핀 층 수 및 두께가 포함되도록 할 수 있다.In this case, when the graphene film is selected as the analysis target nano thin film of step (A), the data of step (B) may include the graphene layer number and thickness of the analysis target graphene film.
상기 (B)단계의 검량선은 상기 기준 그래핀의 층 수 별 FWHM이 하기 [도출범위]에 부합하는 조건에서 작성된 것으로서, 상기 분석대상 그래핀막의 그래핀 층 수를 측정할 때, 밀러지수가 (002)인 그래핀 결정면의 회절 피크가 관찰되는 경우 상기 검량선과 대비하여 그래핀 층 수를 도출할 수 있다.The calibration curve of step (B) is made under the condition that the FWHM for each layer of the reference graphene meets the following [Derivation range], and when measuring the graphene layer number of the graphene film to be analyzed, the Miller index ( When the diffraction peak of the graphene crystal plane of 002) is observed, the number of graphene layers can be derived from the calibration curve.
[도출범위][Derivation range]
① 그래핀 3층 : 4.663~5.069˚±1.5˚① Graphene 3 layer: 4.663 ~ 5.069˚ ± 1.5˚
② 그래핀 4층 : 3.207~3.310˚±1.0˚② Graphene 4 layer: 3.207 ~ 3.310˚ ± 1.0˚
③ 그래핀 5층 : 1.798~1.8440˚±0.5˚③ Graphene 5F: 1.798 ~ 1.8440˚ ± 0.5˚
④ 그래핀 6층 : 1.510~1.5510˚±0.4˚④ 6 layers of graphene: 1.510 ~ 1.5510˚ ± 0.4˚
⑤ 그래핀 7층 : 1.255~1.296˚±0.4˚⑤ Graphene 7F: 1.255 ~ 1.296˚ ± 0.4˚
또한 상기 (B)단계에서는 하기 [그래핀 두께 산출식 1] 또는 [그래핀 두께 산출식 2]에 의해 분석대상 그래핀막의 두께를 측정할 수 있다.In addition, in the step (B), the thickness of the graphene film to be analyzed may be measured by the following [graphene thickness calculation formula 1] or [graphene thickness calculation formula 2].
[그래핀 두께 산출식 1][Calculation of Graphene Thickness 1]
원자 중심간 거리를 기준으로 한 분석대상 그래핀막의 두께(D1) = d002 × (NL-1)Thickness of the graphene film to be analyzed based on the distance between atomic centers (D1) = d 002 × (N L -1)
d002 : 결정면의 밀러지수가 (002)인 다층 기준 그래핀의 층간간격d 002 : Interlayer spacing of multilayer reference graphene having Miller index of crystal plane (002)
NL : 분석대상 그래핀막의 그래핀 층 수N L : Number of graphene layers in the graphene film to be analyzed
[그래핀 두께 산출식 2]Graphene Thickness Calculation Equation 2
원자의 최대 외경간 거리를 기준으로 한 분석대상 그래핀막의 두께(D2) = d002 × NL The thickness of the graphene film to be analyzed (D2) based on the maximum outer-diameter distance of atoms = d 002 × N L
d002 : 결정면의 밀러지수가 (002)인 다층 그래핀의 층간간격d 002 : Interlayer spacing of multilayer graphene with Miller index of crystal plane (002)
NL : 분석대상 그래핀막의 그래핀 층 수N L : Number of graphene layers in the graphene film to be analyzed
한편, 상기 (B)단계의 검량선은 기준 그래핀의 층 수 별 FWHM을 y축으로 하고, 상기 기준 그래핀의 두께(D)로부터 구한 그래핀 두께의 역수(1/D)를 x축으로 하여 얻어낸 직선의 기울기 14~40, y절편 -2~2 조건이 충족되도록 할 수 있다.On the other hand, the calibration curve of step (B) is the y-axis FWHM for each layer of the reference graphene, and the inverse (1 / D) of the graphene thickness obtained from the thickness (D) of the reference graphene as the x-axis The conditions of the obtained straight line 14-40 and y-intercept -2-2 can be satisfied.
본 발명에서는 상기과제들을 해결하고자 극한 초박막 물질의 일종인 극한 초박막 그래핀을 이용하여 상기 과제들을 해결하였다. 추가로 두께의 정의가 명확하고 약 3.5nm 두께 차이를 갖는 7종의 시편 후보를 도출하고 이에 따른 엑스선 분석 방법을 확립하였다.In order to solve the above problems, the present invention has been solved by using an ultra-thin graphene, which is a kind of ultra-thin film material. In addition, seven specimen candidates with a clear definition of thickness and a difference of about 3.5 nm in thickness were derived and the X-ray analysis method was established accordingly.
(1) 구체적으로 도출된 극한 초박막 그래핀 시편들은 1층(3.5Å 이하), 2층(~7Å), 3층(~10.5Å), 4층(~14Å), 5층(~17.5Å), 6층(~21Å), 7층(~24.5Å)} 이다.(1) The ultra-thin graphene specimens specifically derived are 1 layer (3.5Å or less), 2 layer (~ 7Å), 3 layer (~ 10.5Å), 4 layer (~ 14Å), 5 layer (~ 17.5Å) , 6th floor (~ 21Å), 7th floor (~ 24.5Å)}.
(2) 상기 극한 박막 그래핀 시편의 환경적 요인인 온도 및 습도는 278~328켈빈온도(5~55℃) 및 습도가 70% 미만으로 유지되어야 하며, 이 조건을 벗어날 경우 엑스선 분선에 심각한 문제가 발생한다.(2) The environmental factors of temperature and humidity of the extreme thin graphene specimens should be maintained at 278 ~ 328 Kelvin (5 ~ 55 ℃) and humidity below 70%. If this condition is exceeded, serious problems with X-ray separation Occurs.
(3) 상기 그래핀 시편의 스펙인 경우 본 발명에서는 그래핀 층 수가 1~10층이며, 시편의 크기는 0.3cm×0.3cm 이상이다.(3) In the case of the specification of the graphene specimen in the present invention, the number of graphene layers is 1 to 10 layers, and the size of the specimen is 0.3 cm × 0.3 cm or more.
(4) 상기 조건 범위 내에서 필수적인 엑스선 조사장치는 평행빔 엑스선 빔 광학계 (Parallel beam X-ray optics), Array 타입 검출기, ω-2θ 측정방법, Rocking curve 측정법, 엑스선 조사기 회전방법, 시편 회전 방법, 검출기 회전방법, 그래핀 투과 엑스선, 그래핀 결정의 엑스선 결정회절 방법, 그래핀 (002) 특정 결정면의 회절 방법, 엑스선 회절 장치 전체 구성요소 등이 있다.(4) The essential X-ray irradiation apparatus within the above condition ranges are parallel beam X-ray optics, array type detector, ω-2θ measuring method, rocking curve measuring method, X-ray irradiator rotating method, specimen rotating method, Detector rotation method, graphene transmission X-ray, X-ray crystal diffraction method of graphene crystal, diffraction method of graphene (002) specific crystal plane, X-ray diffraction apparatus overall components, and the like.
따라서 상기 조건들을 만족해야 극한 초박막 그래핀의 엑스선 분석이 가능해진다.Therefore, the above conditions must be satisfied to enable X-ray analysis of ultra-thin graphene.
본 발명은 이상의 조건 충족을 위한 X선 분석 장치로서, 「온도조건 278~328°K 및 습도조건 70% 미만으로 제어되며 시편이 안치되는 챔버; 상기 챔버내 시편에 X선을 조사하는 평행빔 X선 조사장치; 및 상기 챔버 내 시편을 투과하거나 상기 시편에 부딛혀 반사 또는 회절하는 X선을 검출하는 검출장치; 를 포함하여 구성되는 X선 분석 장치」를 제공한다.The present invention is an X-ray analysis apparatus for satisfying the above conditions, "the temperature control 278 ~ 328 ° K and humidity conditions less than 70% chamber and the specimen is placed; A parallel beam X-ray irradiator for irradiating X-rays to the specimen in the chamber; And a detection device that detects X-rays that transmit or reflect or diffract the specimen in the chamber. It provides an X-ray analysis apparatus configured to include.
또한, 본 발명은 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법으로서, 「(a) 제21항 내지 제26항 중 어느 한 항의 X선 분석 장치를 준비하는 단계; (b) 상기 챔버에 층수 1~10층, 크기 0.3×0.3㎝ 이상인 그래핀 시편을 안치시키는 단계; 및 (c) 상기 평행빔 X선 조사장치로 상기 그래핀 시편에 X선을 조사하여 투과하거나 회절 또는 반사된 X선을 상기 검출장치로 검출하여 분석하는 단계; 를 포함하는 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법」을 함께 제공한다.In addition, the present invention is an X-ray analysis method for graphene having an extremely fine thickness, "(a) preparing an X-ray analysis device of any one of claims 21 to 26; (b) placing the graphene specimen having a layer number of 1 to 10 layers and a size of 0.3 × 0.3 cm or more in the chamber; And (c) detecting and analyzing X-rays transmitted or diffracted or reflected by the detection apparatus by irradiating X-rays on the graphene specimen with the parallel beam X-ray irradiation apparatus. X-ray analysis method for graphene having an extremely fine thickness comprising a.
본 발명의 그래핀은 CVD 법으로 만들어진 그래핀, 및 이들을 물리적, 기계적, 전기화학적, 화학적으로 변형시킨 산화 그래핀 혹은 모디파이 그래핀, 흑연으로부터 물리적, 화학적, 기계적으로 박리시킨 그래핀, 흑연을 화학적으로 산화시킨 흑연산화물 (그래핀의 일종임) 혹은 그래핀 산화물, 흑연산화물 혹은 그래핀 산화물을 열적으로 환원시킨 그래핀 및 화학적으로 환워시킨 그래핀, 팽창흑연 (expanded graphene: intercalated carbon compound를 열적 혹은 마이크로웨이브 혹은 에너지 인가에 인하여 팽창된 소재)으로부터 제조된 그래핀 나노플레이트, 흑연을 물리화학적 혹은 용매를 이용하여 박리시킨 그래핀, 탑다운 형식으로 제조된 그래핀, 바텀업으로 합성된 그래핀, 촉매에 기반하여 생성된 그래핀, 하이드로카본의 분해를 통하여 제조된 그래핀, SiC 표면에 형성된 그래핀, 나노입자 표면에 캡슐화된 그래핀, RGO, 그래핀 나노플레이트를 물리적, 화학적, 전기적으로 변형시킨 모디파이 그래핀 나노플레이트 등이 있다.The graphene of the present invention is graphene made by CVD, and graphene oxide or modiphy graphene physically, mechanically, electrochemically and chemically modified, graphene physically, chemically and mechanically separated from graphite, graphite Thermally reducing chemically oxidized graphite oxide (a type of graphene) or graphene oxide, graphene oxide or graphene oxide thermally reduced, and chemically oxidized graphene, expanded graphene (intercalated carbon compound) Or graphene nanoplates prepared from microwaves or expanded materials due to energy application, graphene exfoliated graphite using physicochemical or solvent, graphene manufactured in top-down format, graphene synthesized from bottom-up On the surface of graphene and SiC produced through decomposition of graphene and hydrocarbons Formed graphene, graphene encapsulated on the surface of the nanoparticles, RGO, graphene nanoplates physically, chemically and electrically modified, such as graphene nanoplates.
또한 그래핀 표면은 산소가 무조건적으로 존재함이 알려져 있어 본 발명의 그래핀은 산소함량이 5% 이하임을 특징으로 하며, 흑연의 화학적 산화과장을 통하여 황 및 인 성분들이 5% 이하로 함유될 수 있다.In addition, the graphene surface is known that the oxygen is unconditionally present, the graphene of the present invention is characterized in that the oxygen content of 5% or less, sulfur and phosphorus components may be contained less than 5% through the chemical oxidation of graphite. have.
또한 본 발명의 그래핀은 상기 그래핀들이 통상적인 도핑 공정을 통하여 보론, 인, 황, 질소, 불소 등의 원소들이 도핑 되어 있을수 있다.In addition, the graphene of the present invention may be doped with elements such as boron, phosphorus, sulfur, nitrogen, fluorine through the conventional doping process.
또한 본 발명의 그래핀은 상기 그래핀들이 추가적인 화학반응 혹은 표면처리 혹은 후처리 공정을 통하여 그래핀 표면에 다양한 그룹들을 가질 수 있으며, 변현된 치환기들을 자질 수 있다. 대표적인 예로서 OH, -COOH, -CONH2, -NH2, -COO-, -SO3-, -NR3+, -CH=O, C-OH, >O, C-X 기능성 기들을 가지고 있으며, 본 발명의 흑연산화물의 범위에 들어간다.In addition, the graphene of the present invention may have various groups on the graphene surface through the additional chemical reaction or surface treatment or post-treatment process, it is possible to cut the substituted substituents. Typical examples include OH, -COOH, -CONH 2 , -NH 2 , -COO-, -SO 3- , -NR 3+ , -CH = O, C-OH,> O and CX functional groups. It falls within the scope of the graphite oxide of the invention.
본 발명의 상기 그래핀 소재들은 다양한 형태로 더 추가될 수 있으며, 본 발명의 기준은 표면 산화기, 기능성기, functional group, basal plane의 결함정도, modified functional group, 도핑원소, 산소 및 황 함량 등에 상관없이 1~10층의 basal plan의 수이다.The graphene materials of the present invention may be further added in various forms, the criterion of the present invention is the surface oxidizer, functional group, functional group, degree of defects in the basal plane, modified functional group, doping element, oxygen and sulfur content, etc. Regardless of the basal plan on floors 1-10.
전술한 본 발명에 따르면, 기존에 수행할 수 없었던 3nm이하의 극한박막 혹은 층 수가 1~10층인 극한 박막 그래핀의 엑스선 분석 및 엑스선 회절분석을 통하여 결정학적 정보를 얻어낼 수 있다. 물성 분석이 가능해짐에 따라 차세대 신소재로 각광받는 그래핀의 산업적 응용도 가능해진다. 또한 이들 엑스선 분석 정보를 레퍼런스로 하여 미지 그래핀의 결정학적 정보 및 층 수 정보를 알아 낼 수 있다. 이는 그동안 명확하지 않았던 그래핀 소재의 기본 스펙 (층 수 혹은 두께 등)이 명확하게 되고 이를 바탕으로 향후 그래핀 제품의 다양성과 확실성, 완제품의 신뢰성 확보 및 제품 경쟁력을 크게 강화시킬 수 있다.According to the present invention described above, crystallographic information may be obtained through X-ray analysis and X-ray diffraction analysis of an extreme thin graphene having a thickness of 3 nm or less or 1-10 layers which could not be conventionally performed. As the physical property analysis becomes possible, industrial applications of graphene, which is emerging as a next-generation new material, are also possible. In addition, the X-ray analysis information can be used as a reference to determine crystallographic information and layer number information of the unknown graphene. The basic specifications of graphene materials (such as the number of layers or thicknesses), which have not been cleared up until now, become clear, and based on this, it is possible to greatly enhance the diversity and certainty of graphene products, securing reliability of finished products and product competitiveness.
[도 1]은 본 발명이 제공하는 X선 분석 장치의 모식도이다.1 is a schematic diagram of an X-ray analyzing apparatus provided by the present invention.
[도 2]과 [도 3]은 또 다른 X선 분석 장치의 모식도이다.2 and 3 are schematic diagrams of another X-ray analyzer.
[도 4]는 X선 비투과형 기판 위에 있는 극한 초박막 그래핀에 대한 엑스선 조사각도 및 이로부터 회절 되어 나오는 엑스선의 위치가 시편 상층부의 반구(semisphere)에 모두 위치하게 됨을 나타낸 모식도이다.4 is a schematic diagram showing that the X-ray irradiation angle of the ultra-thin graphene on the X-ray non-transmissive substrate and the X-rays diffracted therefrom are located in the semisphere of the upper layer of the specimen.
[도 5]는 투과형 기판위에 있는 극한 초박막 그래핀에 대한 엑스선 조사각도 및 이로부터 투과되어 나오거나 투고 회절 되어 나오는 엑스선의 위치가 시편 하층부의 반구(semisphere)에 모두 위치하게 됨을 나타낸 모식도이다.FIG. 5 is a schematic diagram showing the X-ray irradiation angle of the ultra-thin graphene on the transmissive substrate and the positions of X-rays transmitted or diffracted by the beams are located in the semispheres of the lower layer of the specimen.
[도 6]은 투과형 기판위에 있는 극한 초박막 그래핀에 대한 엑스선 조사각도 및 이로부터 투과되어 나오거나 투고 회절 되어 나오는 엑스선의 위치가 시편 상층부 반구 및 하층부의 반구(semisphere) 즉 3차원 구 (Sphere) 에 모든 회전된 엑스선이 위치하게 됨을 나타낸 모식도이다.FIG. 6 shows the X-ray irradiation angle of the ultra-thin graphene on the transmissive substrate and the position of the X-rays transmitted or diffracted from the X-rays of the upper and lower hemispheres of the specimen, that is, the three-dimensional sphere (Sphere) It is a schematic diagram showing that all rotated X-rays are located at.
[도 7]은 X선 투과형 그래핀 혹은 X선 비투과형 그래핀 시편을 제조하는 방법의 모식도이다.7 is a schematic diagram of a method of manufacturing an X-ray transmissive graphene or X-ray non-transmissive graphene specimen.
[도 8]은 그래핀 시편을 정착시키고 처리하는 방법에 관한 모식도이다.FIG. 8 is a schematic diagram of a method for fixing and processing graphene specimens. FIG.
[도 9]는 단층 그래핀 박막을 전사법을 이용하여 1층에서 10층까지 적층시켜 만든 시료의 XRD 패턴 그래프이다(평탄율을 좋게 하기 위하여 1cm×1cm 실리콘기판에 실리콘 산화막을 형성시키고 그 위에 전사시킨 것임, S1~S10은 각 시료의 이름).FIG. 9 is an XRD pattern graph of a sample obtained by laminating a single layer graphene thin film from one layer to ten layers by using a transfer method (in order to improve the flatness, a silicon oxide film was formed on a 1 cm × 1 cm silicon substrate and S1 to S10 are the names of each sample).
[도 10]은 [도 9]의 (002) 피크를 해석하여 표로 나타낸 데이터 값이다.FIG. 10 is a table of data values obtained by analyzing the (002) peak in FIG. 9.
[도 11]은 [도 10]의 데이터를 해석하여 S1~S10 시료들에 대하여 절대적인 그래핀 층 수를 결정하여 나타낸 값이다.FIG. 11 is a value showing an absolute graphene layer number determined for S1 to S10 samples by analyzing the data of FIG. 10.
[도 12]는 [도 11]의 값들을 이론치와 비교하며 도시한 그래프이다.FIG. 12 is a graph comparing the values of FIG. 11 with theoretical values. FIG.
[도 13]은 GI SAXS법을 이용하여 찾아낸 7층 그래핀의 (hkl) 피크를 나타낸 그래프이다.FIG. 13 is a graph showing (hkl) peaks of 7-layer graphene found using the GI SAXS method. FIG.
[도 14]는 그래핀 결정의 배향성을 보여주는 록킹커브(Rocking curve) 그래프이다.14 is a rocking curve graph showing the orientation of graphene crystals.
[도 15]는 시편이 3축으로 축회전하는 것에 대한 모식도이다.FIG. 15 is a schematic diagram of the axis of rotation of the specimen in three axes. FIG.
[도 16]은 평행빔 X선 조사장치와 검출장치가 종방향과 횡방향으로 원심회전하는 것의 모식도이다.FIG. 16: is a schematic diagram of a centrifugal rotation of a parallel beam X-ray irradiation apparatus and a detection apparatus in a longitudinal direction and a lateral direction.
이하에서는 첨부된 도면과 함께 본 발명을 상세히 설명하기로 한다.Hereinafter, the present invention will be described in detail with the accompanying drawings.
본 발명은 「온도조건 278~328°K 및 습도조건 70% 미만으로 제어되며 시편이 안치되는 챔버; 상기 챔버 내 시편에 X선을 조사하는 평행빔 X선 조사장치; 및 상기 챔버 내 시편을 투과하거나 상기 시편에 부딛혀 반사 또는 회절하는 X선을 검출하는 검출장치; 를 포함하여 구성되는 X선 분석 장치」를 제공한다. 상기 챔버의 온도조건 및 습도조건에 관한 사항은 후술하기로 한다.The present invention is a chamber that is controlled under a temperature condition of 278 ~ 328 ° K and a humidity condition of less than 70% and the specimen is placed; A parallel beam X-ray irradiation apparatus for irradiating X-rays to the specimen in the chamber; And a detection device that detects X-rays that transmit or reflect or diffract the specimen in the chamber. It provides an X-ray analysis apparatus configured to include. Details of the temperature and humidity conditions of the chamber will be described later.
상기 챔버 내에는 분석 대상 시편을 안치시키는데, 안치된 시편을 3축(x-y-z축)으로 축회전시킬 수 있는 시편고정대를 챔버 내에 구비시킬 수 있다. [도 15]는 시편이 3축으로 축회전하는 것에 대한 모식도이다.In the chamber, the specimen to be analyzed is placed. A specimen holder capable of axially rotating the placed specimen in three axes (x-y-z axis) may be provided in the chamber. FIG. 15 is a schematic diagram of the axis of rotation of the specimen in three axes. FIG.
또한 상기 평행빔 X선 조사장치는 종방향과 횡방향으로 원심회전하도록 구성할 수 있으며, 상기 검출장치는 종방향과 횡방향으로 원심회전하도록 구성할 수 있다. [도 16]은 평행빔 X선 조사장치와 검출장치가 종방향과 횡방향으로 원심회전하는 것의 모식도이다.In addition, the parallel beam X-ray irradiation apparatus may be configured to centrifugally rotate in the longitudinal direction and the transverse direction, and the detection apparatus may be configured to centrifugally rotate in the longitudinal direction and the transverse direction. FIG. 16: is a schematic diagram of a centrifugal rotation of a parallel beam X-ray irradiation apparatus and a detection apparatus in a longitudinal direction and a lateral direction.
[도 1]은 본 발명이 제공하는 X선 분석 장치의 모식도이다. [도 1]에 도시된 실시예는 평행빔 X선 조사장치를 고정시키고 시편을 일축 회전시킴으로써 조사각(ω)을 설정토록 구성된 것이다. 조사각(ω)은 조사된 X선과 시편이 이루는 각도를 의미한다. 이때 검출장치는 조사되는 X선을 기준으로 각도 2θ(ω=θ) 지점에 위치한다. 이러한 조사각과 검출장치의 위치설정을 2θ(쎄타)-ω(오메가)방법이라 한다.1 is a schematic diagram of an X-ray analyzing apparatus provided by the present invention. The embodiment shown in FIG. 1 is configured to set the irradiation angle ω by fixing the parallel beam X-ray irradiation apparatus and uniaxially rotating the specimen. Irradiation angle (ω) means the angle between the irradiated X-ray and the specimen. At this time, the detection device is located at an angle 2θ (ω = θ) point with respect to the X-ray to be irradiated. This irradiation angle and positioning of the detection device are referred to as 2θ (theta) -ω (omega) method.
상기 2θ-ω 방법은 평행빔 X선 조사장치를 고정시키고 시편의 일축 회전각에 따라 검출장치를 이동시키는 방법, 검출장치를 고정시키고 시편의 일축 회전각에 따라 평행빔 X선 조사장치를 이동시키는 방법 등을 포함한다.The 2θ-ω method is a method of fixing a parallel beam X-ray irradiation apparatus and moving the detection device according to the uniaxial rotational angle of the specimen, and fixing the detection device and moving the parallel beam X-ray irradiation apparatus according to the uniaxial rotational angle of the specimen. Method and the like.
예를 들어 X선 조사각(ω)을 아주 작은 각도로 한 후 검출장치를 조사되는 X선을 기준으로 2θ 각도로 회동시킬 수 있다. 이 방법은 GI(Grazing incident) 방법이며, GI-SAXS 방법도 이에 해당한다. 또한 실리콘 기판에 그래핀이 코팅된 시편의 경우 기판의 강한 피크의 영향을 줄이기 위하여 검출장치를 그래핀(hkl) 결정면의 피크(주로 (002) 피크)가 나오는 위치에 고정시키고 X선 조사각(ω)을 변화시키는 방법도 있다.For example, the X-ray irradiation angle ω may be set to a very small angle, and then the detector may be rotated at an angle of 2θ with respect to the X-ray radiated. This method is a GI (Grazing incident) method, GI-SAXS method also corresponds to this. In addition, in the case of the specimen coated with graphene on the silicon substrate, in order to reduce the influence of the strong peak of the substrate, the detector is fixed at the position where the peak of the graphene (hkl) crystal plane (mainly (002) peak) comes out and the X-ray irradiation angle ( There is also a method of changing ω).
또한 상기 시편은 3축 회전에 의한 각도설정이 가능하다([도 1]에서의 ψ(프사이) 및 Φ(파이)). 시편의 3축 회전각 설정에 따라 시편 상부의 부분적인 공간에 대한 엑스선 조사각도 및 검출기 각도의 확보가 가능하다. 이에 따라 시편 상층부에 존재하는 회절된 X선들을 부분적으로 검출할 수 있게 된다.In addition, the specimen can be set by the three-axis rotation angle (φ (psi) and Φ (pie) in Fig. 1). According to the 3-axis rotation angle setting of the specimen, it is possible to secure the X-ray irradiation angle and the detector angle with respect to the partial space on the upper portion of the specimen. This allows partial detection of diffracted X-rays present in the upper layer of the specimen.
극한 초박막 그래핀이 경우에는 기판이 없는 시편을 적용할 수 있다. 즉 에칭기술을 활용하여 떼어낸 그래핀 시편을 적용할 수 있는데, 이 경우에는 시편의 손상이 우려된다. 이러한 경우에는 시편을 한정적으로 움직이고, 대신 엑스선 조사각도 및 검출장치 위치에 대한 각도의 자유도를 극대화 시킴으로서 문제를 해결할 수 있다. 평행빔 X선 조사장치를 종방향과 횡방향으로 원심회전하도록 구성함으로써 특정 공간의 모든 공간좌표에 대해 X선을 제공할 수 있다.In the case of extreme ultra-thin graphene, a specimen without a substrate may be applied. In other words, it is possible to apply the removed graphene specimen using an etching technique, in which case the specimen may be damaged. In this case, the problem can be solved by maximally moving the specimen and maximizing the degree of freedom of X-ray irradiation angle and the angle of the detection device. By configuring the parallel beam X-ray irradiation apparatus to be centrifugally rotated in the longitudinal direction and the transverse direction, X-rays can be provided for all spatial coordinates in a specific space.
본 발명에서 X선 조사각도, 시편의 배치(각도) 및 검출장치의 배치(각도)가 중요한 극한 초박판 그래핀 시편에 대한 3차원적인 결정구조 혹은 특정 결정면(예를 들어 (002)면)에 대한 3차원적인 피크 형태, 혹은 대칭 결정구조에서 상하부 결정면의 차이점 등을 분석하기 위하여 기존의 장치 기술들의 한계를 뛰어넘을 필요가 있기 때문이다.In the present invention, the X-ray irradiation angle, the arrangement (angle) of the specimen, and the arrangement (angle) of the detection device are important in a three-dimensional crystal structure or a specific crystal plane (for example, the (002) plane) for the ultra-thin graphene specimen. This is because it is necessary to overcome the limitations of existing device technologies in order to analyze the three-dimensional peak shape or the difference between the upper and lower crystal planes in the symmetric crystal structure.
구체적으로 X선 비투과형 기판에 그래핀막이 형성되거나 배치된 시편의 경우, X선 조사각도에 따라 회절되어 나오는 X선의 위치는 [도 4]에 도시된 것처럼 시편 상부의 반구(semisphere)에 모두 위치할 수 있게 된다(시편의 하부 반구는 제외). 따라서 시편은 3축(x,y,z)으로 축회전하고, 평행빔 X선 조사장치 및 검출장치는 종방향과 횡방향으로 원심회전할 수 있을 때 모든 위치의 X선 검출이 수월해진다.Specifically, in the case of the specimen in which the graphene film is formed or disposed on the X-ray non-transmissive substrate, the positions of the X-rays diffracted according to the X-ray irradiation angle are all located in the semisphere on the upper part of the specimen as shown in FIG. (Except for the lower hemisphere of the specimen). Therefore, when the specimen is axially rotated in three axes (x, y, z), and the parallel beam X-ray irradiation apparatus and the detection apparatus can be centrifugally rotated in the longitudinal and transverse directions, X-ray detection at all positions is facilitated.
다른 예로 X선 투과형 기판에 그래핀막이 형성되거나 배치된 시편의 경우 또는 기판을 에칭하여 그래핀막만을 시편으로 하는 경우(free standing), 투과된 X선 또는 투과하며 회절된 X선의 위치는 [도 5]에 도시된 것처럼 시편 하부의 반구(semisphere)에 위치할 수 있게 된다. 이 경우에도 시편은 3축(x,y,z)으로 축회전하고, 평행빔 X선 조사장치 및 검출장치는 종방향과 횡방향으로 원심회전할 수 있을 때 모든 위치의 X선 검출이 수월해진다.As another example, when the graphene film is formed or disposed on the X-ray transmissive substrate or when the substrate is etched to free the graphene film only (free standing), the position of the transmitted X-ray or the transmitted and diffracted X-ray is shown in FIG. 5. Can be placed in the semisphere at the bottom of the specimen. Even in this case, the specimen is axially rotated in three axes (x, y, z), and the parallel beam X-ray irradiator and detector can be centrifugally rotated in the longitudinal and transverse directions to facilitate the detection of X-rays at all positions. .
한편, X선 반투과형 기판에 그래핀막이 형성되거나 배치된 경우에는 X선의 일부는 투과되고 일부는 반사(회절)되어 [도 6]에 도시된 바와 같이 시편 상부와 하부의 모든 공간 즉, 3차원 구(Sphere)에 회절된 엑스선이 위치할 수 있게 된다. 이 경우에도 시편은 3축(x,y,z)으로 축회전하고, 평행빔 X선 조사장치 및 검출장치는 종방향과 횡방향으로 원심회전할 수 있을 때 모든 위치의 X선 검출이 수월해진다.On the other hand, when the graphene film is formed or disposed on the X-ray transflective substrate, part of the X-ray is transmitted and part is reflected (diffraction), so that all spaces of the upper and lower portions of the specimen, that is, three-dimensional, as shown in FIG. The diffracted X-rays can be located in the sphere. Even in this case, the specimen is axially rotated in three axes (x, y, z), and the parallel beam X-ray irradiator and detector can be centrifugally rotated in the longitudinal and transverse directions to facilitate the detection of X-rays at all positions. .
X선 투과형 기판을 사용하는 시편을 적용할 때에는 기판의 재질, 두께 및 투과율을 확인해야 한다. X선 투과형 기판으로는 플라스틱 기판, 세라믹 기판, 다공성 기판, 섬유복합체 기판 등을 선택할 수 있으며 기판 두께에 따른 투과율을 확인한 후 적용이 가능하다. X선 투과형 기판을 사용한 그래핀 시편을 제조하는 여러 가지 방법은 [도 7]에 나타내었다.When applying specimens using X-ray transmissive substrates, the material, thickness and transmittance of the substrate should be checked. As the X-ray transmissive substrate, a plastic substrate, a ceramic substrate, a porous substrate, a fiber composite substrate, and the like can be selected, and the application can be applied after confirming the transmittance according to the substrate thickness. Various methods of preparing graphene specimens using the X-ray transmissive substrate are shown in FIG. 7.
한편, 본 발명이 제공하는 X선 분석 장치는 상기 챔버 내 시편에 열을 가하는 열처리장치가 구비될 수 있다. 또한, 상기 챔버 내 시편에 수분을 가하는 가습장치가 함께 구비될 수 있다. 상기 열처리장치 및 가습장치에 대한 상세 사항은 후술하기로 한다.On the other hand, X-ray analysis apparatus provided by the present invention may be provided with a heat treatment device for applying heat to the specimen in the chamber. In addition, a humidifier for applying moisture to the specimen in the chamber may be provided together. Details of the heat treatment apparatus and the humidifier will be described later.
본 발명은 「(a) 전술한 X선 분석 장치를 준비하는 단계; (b) 상기 챔버에 층수 1~10층, 크기 0.3×0.3㎝ 이상인 그래핀 시편을 안치시키는 단계; 및 (c) 상기 평행빔 X선 조사장치로 상기 그래핀 시편에 X선을 조사하여 투과하거나 회절 또는 반사된 X선을 상기 검출장치로 검출하여 분석하는 단계; 를 포함하는 극미세 두께를 갖는 그래핀에 대한 X선 분석방법」을 함께 제공한다. 상기 그래핀 시편의 층수 및 크기에 관한 자세한 사항은 후술하기로 한다. The present invention provides a method for preparing an X-ray analyzer; (b) placing the graphene specimen having a layer number of 1 to 10 layers and a size of 0.3 × 0.3 cm or more in the chamber; And (c) detecting and analyzing X-rays transmitted or diffracted or reflected by the detection apparatus by irradiating X-rays on the graphene specimen with the parallel beam X-ray irradiation apparatus. X-ray analysis method for graphene having an ultra-fine thickness including a. Details of the number and size of the graphene specimens will be described later.
상기 (c)단계에서는 브래그법칙에 의해 회절된 X선을 분석할 수 있다. 그러나 브래그 법칙에 의해 회절되지 않은 직접 투과형 엑스선, 흡수된 엑스선 탄성산란, 비탄성 산란의 분석방법도 적용 가능하다. 예를 들어 브래그 법칙에 맞지 않은 일정 조사각도(즉, 그래핀 시편 평면부의 수직방향)로 그래핀에 엑스선을 조사하고 반대측부에 검출기를 위치시켜 직접적으로 투과하여 나오는 엑스선들을 분석할 수 있다.In the step (c) it is possible to analyze the X-ray diffracted by the Bragg law. However, the method of analyzing direct transmission X-rays, absorbed X-ray elastic scattering, and inelastic scattering, which are not diffracted by Bragg's law, is also applicable. For example, X-rays may be irradiated onto graphene at a certain irradiation angle (ie, the vertical direction of the graphene specimen plane) that does not conform to Bragg's law, and the detector may be positioned on the opposite side to analyze the X-rays that pass through directly.
구체적인 실시예로 그래핀 시편 S3~S6(숫자는 그래핀의 층 수를 나타낸다)은 그래핀 1층당 0.5~1%의 엑스선 흡수율을 보였는데 이는 회절 인자만에 의한 것이 아니라 그래핀 층 수별 엑스선 흡수 물성을 보여주는 결과이다. 향후 조사각 및 층 수별 추가연구가 필요하다.As a specific example, the graphene specimens S3 to S6 (the numbers represent the number of layers of graphene) showed X-ray absorption of 0.5-1% per layer of graphene, which is not based on diffraction factor alone, but X-ray absorption per graphene layer. This shows the physical properties. Further research is needed for each survey angle and number of floors.
상기 (b)단계에서는 여러 가지 그래핀 시편을 안치시킬 수 있다.In the step (b) it can be placed a variety of graphene specimens.
[도 7]의 (a)는 CVD 그래핀을 이용한 그래핀 시편 제조방법을 모식적으로 도시한 것이다. X선을 투과시키기 위해서는 기판 에칭기술을 이용하여 기판의 하부가 일부 비어있게 한 시편(A type), 기판을 완전히 제거한 시편(B type), B type 시편을 다른 기판에 전사한 시편(C type), 전사 기판에 대해 추가적인 부분에칭 또는 완전 에칭을 실시하여 제조한 시편(D type) 등을 사용할 수 있다. C type 시편의 X선의 투과성을 높이기 위하여 다공성 기판, 에칭된 기판, 메쉬기판 등이 사용될 수 있다.(A) of FIG. 7 schematically shows a method for preparing graphene specimens using CVD graphene. In order to transmit X-rays, a substrate (A type), a specimen completely removed from the substrate (B type), and a B type specimen transferred to another substrate (C type) using a substrate etching technique. A specimen (D type) manufactured by performing additional partial etching or complete etching on the transfer substrate may be used. Porous substrates, etched substrates, mesh substrates, etc. may be used to increase the X-ray transmittance of C-type specimens.
[도 7]의 (b)는 그래핀 분말 또는 분산 그래핀을 이용한 시편 제조방법을 모식적으로 도시한 것이다. 이에 따라 그래핀 분말의 경우 분말 자체를 압착하여(면간 결합력에 의하여 필름형태 유지함) 제조한 시편(E type), X선 투과형 혹은 비투과형 기판 위에 그래핀 분말을 프레싱하거나 코팅한 시편(F type), 메쉬기판, 다공성기판, 에칭된 기판 등에 분말을 프레싱하거나 코팅한 시편(G type) 등을 얻을 수 있으며, 이 시편들의 기판에 대해 에칭을 실시한 시편(H type)을 제조할 수도 있다. 이때 사용되는 그래핀 분말들은 산소가 5% 미만 도핑된 그래핀, 열환원 그래핀, 화학적환원그래핀, 그래핀산화물(표면산화기 및 Modified된 치환기 등), 흑연의 볼밀링 결과물, 흑연의 고에너지 볼밀링 결과물, 화학반응적 볼밀링(볼밀링+화학반응(액상 및 기상), 볼밀링+이산화탄소반응 등) 결과물, 팽창흑연으로부터 제조되는 그래핀 나노플레이트가 포함된다. 산화기가 포함된 그래핀 혹은 그래핀 산화물에는 별도로 열처리를 하여 그래핀 (002) 결정면의 변화 순간이 가장 잘 관찰되도록 할 수 있다.(B) of FIG. 7 schematically illustrates a test piece manufacturing method using graphene powder or dispersed graphene. Accordingly, in the case of graphene powder, the powder itself is pressed (to maintain the film form by the interfacial bonding force), the specimen (E type), and the graphene powder is pressed or coated on the X-ray transmissive or non-transmissive substrate (F type) In addition, a specimen (G type) obtained by pressing or coating a powder on a mesh substrate, a porous substrate, an etched substrate, or the like can be obtained, and a specimen (H type) etched with respect to the substrate of these specimens can be prepared. The graphene powders used here are graphene doped with less than 5% oxygen, heat-reduced graphene, chemically-reduced graphene, graphene oxides (surface oxidizers and modified substituents), ball milling products of graphite, high graphite Energy ball milling products, chemically reactive ball milling (ball milling + chemical reactions (liquid and gas phase), ball milling + carbon dioxide reactions, etc.), graphene nanoplates prepared from expanded graphite. Graphene or graphene oxide containing an oxidizer may be heat treated separately so that the instant of change of the graphene (002) crystal plane is best observed.
[도 8]은 그래핀 시편을 챔버 내에 안치시키는 방법을 나타낸 것이다. 그래핀 시편은 시편고정대에 고정시킬 수 있으며 물리적방법(압착, 누름 등), 기계적방법 (나사 등), 화학적방법(접착제, 페이스트 등), 전자기적방법(정전인력, 정전기필름 등)을 적용할 수 있으며, 반데르발스 힘이나 자기적 힘에 의해 안치, 고정시킬 수 있다.8 shows a method of placing the graphene specimen in the chamber. Graphene specimens can be fixed to the specimen holder, and can be applied by physical methods (compression, pressing, etc.), mechanical methods (screws, etc.), chemical methods (adhesives, pastes, etc.), electromagnetic methods (electrostatic forces, electrostatic films, etc.). It can be settled and fixed by van der Waals force or magnetic force.
본 발명이 제공하는 X선 분석 장치에는 챔버 내의 그래핀 시편에 열을 가하는 열처리장치가 구비될 수 있다. 액상 그래핀 분산액을 기판에 코팅한 후 상기 열처리장치로 가볍게 열처리하면서 과량의 용매 또는 흡착된 용매를 제거할 수 있다. 또한 그래핀 시편에 수분흡착이 의심되거나 수분흡착을 방지하고자 할 경우에도 상기 열처리장치를 통해 안정적인 온도범위 내에서 가온할 수 있다. 또한 상기 열처리장치로 산소기가 함유된 그래핀 혹은 그래핀 산화물류들을 열처리하면서 그래핀 (002)면을 직접 관찰할 수 있다. 일 예로, 그래핀 산화물을 글래스 위에 코팅한 후 50℃에서 열처리하여 과량의 수분을 제거한 시편에 대해 2θ-ω 방법으로 측정한 경우 (002) 결정면이 2θ=11.5°에 위치하였다. 이를 230℃로 열처리 한 결과 2θ=23.3도로 크게 변함을 관찰할 수 있었다. X-ray analysis apparatus provided by the present invention may be provided with a heat treatment device for applying heat to the graphene specimen in the chamber. After coating the liquid graphene dispersion on the substrate, it is possible to remove excess solvent or adsorbed solvent while lightly heat-treated with the heat treatment apparatus. In addition, even when suspected of moisture adsorption on the graphene specimen or to prevent moisture adsorption can be heated in a stable temperature range through the heat treatment apparatus. In addition, the graphene (002) surface can be directly observed while heat-treating graphene or graphene oxides containing oxygen groups with the heat treatment apparatus. For example, when the graphene oxide was coated on glass and then heat treated at 50 ° C. to remove excess moisture, the (002) crystal plane was positioned at 2θ = 11.5 °. It was observed that the heat treatment at 230 ℃ significantly changed 2θ = 23.3 degrees.
[도 8]의 (c)는 극한 초박판 그래핀 시편의 물성 변화 효과를 극대화시키고자 고안한 개념이다. 그래핀을 잡아당기는 경우 약 30%까지 늘어나더라도 그래핀 내부의 층간 결합이 끊어지지 않음이 밝혀졌는데 아직 이에 대한 XRD 연구 결과는 없다. 따라서 상기 시편고정대에는 [도 8]의 (c) 도면처럼 그래핀 시편을 잡아 고정시키는 고정부(체결형 등)가 그래핀 시편의 테두리측에 2방향 또는 4방향으로 구비될 수 있으며, 2방향 또는 4방향의 고정부는 마주보는 2개가 한 쌍으로 거동하도록 구성할 수 있다. 즉, 상기 그래핀 시편을 잡아 고정시킨 채 상기 마주보는 한 쌍의 고정부를 마이크로단위로 벌려는 미세연신장치를 구비할 수 있다. 8 (c) is a concept designed to maximize the effect of changing the physical properties of the ultra-thin graphene specimens. It has been found that pulling up graphene does not break the interlayer bonds inside the graphene even if it is stretched by about 30%. Therefore, the specimen holder may be provided with a fixed portion (fastening type, etc.) to hold and secure the graphene specimen as shown in (c) of FIG. 8 in two or four directions on the edge of the graphene specimen, two directions Alternatively, the four-way fixing part may be configured such that two opposite parts behave in pairs. That is, while holding and fixing the graphene specimen may be provided with a micro-stretching device to open the pair of fixing parts facing each other in micro units.
상기 미세연신장치는 초미세 기계장치를 써서 단계적으로 잡아당길 수 있는 장치 및 피에조 물질을 이용하여 잡아당길 수 있는 장치 등으로 구체화 할 수 있다. 간단한 실시예로서 PET 필름에 전사시킨 CVD 5층 그래핀 시편을 금속판 위에 놓고 시편 양측부 일부 상단부에 PET 필름 보호막을 놓고(그래핀 상부 측면부 위에) 그 위에 급속 판을 대어 꽉 눌러 고정하였다(나사). 또한 일측부는 약 5% 연신시켜 (PET+그래핀 전체) 엑스선 회절을 측정한 결과 층간 간격이 연신 후 약 3~8% 늘어남을 알 수 있었는데 이는 연신에 따른 그래핀 결정의 품질이 떨어져서 생기는 현상으로 설명할 수 있다.The micro-stretching device can be embodied as a device that can be pulled out step by step using an ultra-fine mechanical device and a device that can be pulled out using a piezo material. As a simple example, a CVD 5-layer graphene specimen transferred to a PET film was placed on a metal plate, and a PET film protective film was placed on some upper portions of both sides of the specimen (on the upper side of the graphene). . In addition, one side was stretched by about 5% (PET + graphene) X-ray diffraction, and the interlayer spacing was increased by about 3 to 8% after stretching, which is explained by the poor quality of the graphene crystals due to stretching. can do.
S1 ~ S10 시료S1 to S10 Sample
[도 9]에 나타난 시료 S1~S10은 단층막 그래핀을 전사시켜 1층에서 10층까지 적층시켜 만든 시편이다. 그래핀 결정의 평탄율을 좋게 하기 위하여 1cm ×1cm 실리콘기판에 실리콘 산화막을 형성시키고 그 위에 그래핀을 전사시킨 시료들이다. 시료명은 적층된 층수에 따라 각각 S1~S10으로 명명하였다.Samples S1 to S10 shown in FIG. 9 are specimens made by transferring single layer graphene and laminating them from one layer to ten layers. In order to improve the flatness of the graphene crystals, silicon oxide films were formed on a 1 cm x 1 cm silicon substrate and graphene was transferred thereon. The sample names were named S1 to S10, respectively, according to the number of stacked layers.
S1~S10 시료에서 물리적으로 적층시킨(Layer by layer 적층) 그래핀들이 같은 층의 수를 갖는 그래핀 결정을 형성한다는 것은 아니다. 물리적으로 하나 하나 적층된 그래핀 층의 수는 실제로 결정을 형성하는 층의 수와 같을 수도 있고 다를 수도 있다(결정을 형성하지 않고 공간적으로 들떠있는 상태가 있는 경우 적층수와 결정의 층 수가 달라짐).Graphenes physically stacked (Layer by layer lamination) in S1 to S10 samples do not form graphene crystals with the same number of layers. The number of graphene layers physically stacked one by one may be the same as or different from the number of layers actually forming crystals (the number of layers and the number of layers differs when there is a spatially floating state without forming crystals). .
또한 현재 수작업으로 적층 공정이 이루어지기 때문에 같은 개수의 층을 올린다 해도 매 공정마다 서로 다른 층의 개수를 갖는 그래핀 결정들이 만들어질 확률이 높다. 따라서 본 발명에서 제안된 그래핀 층 수 측정 방법은 이러한 측면에서도 반드시 필요하다. In addition, since the stacking process is performed manually by hand, even if the same number of layers are raised, there is a high probability that graphene crystals having a different number of layers are formed in each process. Therefore, the graphene layer number measuring method proposed in the present invention is also necessary in this respect.
상기 S1~S10 시료에 대한 XRD 패턴을 분석한 결과 각 시료의 그래핀층 수는 적층 회수와 일치하지 않음을 알 수 있있다(한 예로, S10 시료의 그래핀층 수는 7층 이었다). 이에 같은 제조업체에서 같은 종류의 시료를 구매하여 분석한 결과 그래핀의 층 수가 또 다르게 분석되었는바, 그래핀 적층 회수 만으로는 그래핀 결정들의 층 수는 알 수 없다는 것이 결론이었다.As a result of analyzing the XRD patterns of the S1 to S10 samples, it can be seen that the number of graphene layers of each sample does not match the number of stacks (for example, the number of graphene layers of the S10 sample was 7 layers). As a result of purchasing the same type of sample from the same manufacturer and analyzing the graphene layer, it was concluded that the graphene crystallization layer number cannot be known only by the number of graphene stacks.
결론적으로 [도 9]는 세계 최초의 극한 박막의 일종인 그래핀의 두께에 따른 결정의 엑스선 회절 분석 결과이다. 이는 이들의 물성연구 뿐만 아니라 그래핀 층 수 별 절대적 물리량을 제공하고 있어서 세계 어디에서나, 언제든지 레퍼런스로 이용할 수 있는 방법을 제시하고 있다.In conclusion, FIG. 9 is an X-ray diffraction analysis result of a crystal according to the thickness of graphene, which is one of the world's first extreme thin films. This not only studies their physical properties but also provides absolute physical quantities for each graphene layer, suggesting a method that can be used as a reference anywhere in the world.
XRD 측정방법XRD Measurement Method
본 발명에서는 Parallel beam optics, 2theta-omega 모드, rocking curve 측정법, 고정각 입사빔법, GI SAXS법 등이 이용되었다.In the present invention, parallel beam optics, 2theta-omega mode, rocking curve measurement method, fixed angle incident beam method, GI SAXS method, and the like are used.
구체적 예로서 Cu Kα1(1.540598Å), Kα2(1.544426) 선을 강도비 2:1로 혼합한 X선을 사용하였으며, 2θ는 20~50˚, step size는 0.016˚로 균일하게 하였고, 2theta(쎄타)-ω(오메가) 방식으로 측정하였다.As a specific example, X-rays using Cu Kα1 (1.540598Å) and Kα2 (1.544426) lines with an intensity ratio of 2: 1 were used, 2θ was 20-50 °, step size was 0.016 °, and 2theta (Theta) ) -ω (omega) method.
X선은 침투력이 매우 큰 반면, 그래핀막은 매우 얇아 그래핀막을 투과하는 X선의 회절량이 너무 작아 그래핀 (002) 결정면(각 층의 그래핀이 수직으로 적층된 방향의 결정면)의 피크를 얻어내기가 매우 어렵다. 따라서 반드시 평행빔(Parallel beam)으로 고출력 X선(high flux X-ray)을 조사하는 장치가 필수적이다.While X-rays have a very high penetration force, the graphene film is very thin so that the diffraction amount of the X-rays penetrating the graphene film is too small to obtain peaks of the graphene (002) crystal plane (crystal plane in the direction in which the graphene is stacked vertically). It is very difficult to bet. Therefore, a device for irradiating high flux X-rays with a parallel beam is essential.
평행빔 X선 광학기(Parallel beam X-ray optics)로서 본 발명에서는 평행빔 X선 미러(Parallel beam X-ray Mirror)를 사용하였다.As parallel beam X-ray optics, a parallel beam X-ray mirror was used in the present invention.
또한 기판 실리콘의 피크가 너무 강하여 아주 적은 양의 그래핀(002) 피크가 묻힐 수 있다. 따라서 그래핀 (002) 피크만 얻어내기 위해 그래핀(002) 피크가 존재하는 2θ의 1/2의 근처 값을 입사각으로 고정시켜 사용할 수 있다.In addition, the peak of the substrate silicon is so strong that a very small amount of graphene (002) peak can be buried. Therefore, in order to obtain only the graphene (002) peak, a near value of 1/2 of 2θ where the graphene (002) peak is present may be fixed to the incident angle.
또한 이 경우에 그래핀 결정면의 기울어진 정도에 따라 그래핀(002) 결정면의 록킹커브(rocking curve)를 먼저 확인하여 2θ/2 또는 이 근처 값들을 정하여 측정할 수 있다. 이 때 이용가능한 조사각도는 그래핀 (002) 피크 위치 2θ의 (2θ÷2)±1˚의 각도범위 내에서 가능하다. 조사 각도를 정하기 전에 록킹커브(rocking curve) 측정을 통하여 그래핀 (002) 결정면의 배향을 알아보는 것이 바람직하다.In this case, the rocking curve of the crystal surface of the graphene 002 may be determined first by determining the 2θ / 2 or near values according to the inclination degree of the graphene crystal surface. The irradiation angle available at this time is possible within the angle range of (2θ ÷ 2) ± 1 ° of the graphene (002) peak position 2θ. Before determining the irradiation angle, it is preferable to determine the orientation of the graphene (002) crystal plane by measuring a rocking curve.
이와 같은 측정법들은 그래핀 결정이 매우 얇고 결정량에 대한 정보가 너무 적어 주위 백그라운드 및 기판의 영향에 묻히거나 오염될 수 있어 반드시 고려되어야 함을 본 발명을 통해 알 수 있었다.Such measurement methods can be seen through the present invention that the graphene crystal is very thin and the information about the amount of crystal is too small to be buried or contaminated by the influence of the surrounding background and substrate.
다음으로, 앞서 설명한 본 발명의 X선 분석방법에 관한 설명을 정리하면 다음과 같다. Next, a summary of the X-ray analysis method of the present invention described above is as follows.
(1) X선 조사장치 : 평행빔 X선 조사장치(Parallel beam X-ray optics)(1) X-ray irradiation apparatus: Parallel beam X-ray optics
(2) 검출장치 : Array 타입형 검출기(2) Detection device: Array type detector
(3) 측정방법 : 2theta-omega 모드, rocking curve 측정법, 입사각 고정법, GI SAXS, 2D GISAXS법(3) Measuring method: 2theta-omega mode, rocking curve measuring method, incident angle fixing method, GI SAXS, 2D GISAXS method
(4) 그래핀 시편 : 그래핀 층 수 1~10층(두께 3nm 이하), 크기는 0.3×0.3㎝ 이상(4) Graphene specimens: 1-10 layers of graphene layers (3 nm or less in thickness), 0.3 × 0.3 ㎝ or more
(5) 극한 박막의 변질도를 알아보기 위하여 열처리장치 및 가습장치(5) Heat treatment device and humidifier to find out the degree of change of extreme thin film
를 별도로 두어 비교 분석 함.Set aside for comparative analysis.
(6) 시편은 3축(x,y,z축)으로 축회전, 평행빔 X선 조사장치 및 검출(6) Specimen rotates in three axes (x, y, z axis), parallel beam X-ray irradiation device and detection
장치는 종방향과 횡방향으로 원심회전 가능하도록 구성.The device is configured to allow centrifugal rotation in the longitudinal and transverse directions.
(002) 피크 피팅방법(002) Peak fitting method
다층막 그래핀 (002) 피크들은 가우시안 함수(Gaussian function, 이하 'G 함수') 및 로렌찌안 함수(Lorentzian function, 이하 'L 함수')를 이용하여 피크 피팅을 수행하였으며, 본 발명에서는 이들 데이터들을 구체적으로 제공하였다. 그러나, 이들 G 함수 및 L 함수 피팅 이외에도 X-선 회절 피크를 만족시킬 수 있는 함수 또는 프로그램이 있다면 이들을 이용할 수도 있다. 근본적으로 같은 시료의 XRD 피크의 FWHM 및 피크센터는 같은 시간, 장소, XRD 장치에 상관없이 일정한 고유 값이며 노이즈 정도, 피크 피팅 함수 등에 의해 약간의 에러 등이 발생할 수 있다.The multilayer graphene (002) peaks were subjected to peak fitting using a Gaussian function ('G function') and a Lorentzian function ('L function'). Provided. However, in addition to these G and L function fittings, any function or program capable of satisfying the X-ray diffraction peaks may be used. Fundamentally, the FWHM and the peak center of the XRD peak of the same sample are constant eigenvalues regardless of the same time, place, and XRD apparatus, and some errors may occur due to the noise level and the peak fitting function.
[도 9]는 S1~S10에 대한 XRD 측정 데이터를 나타낸 그래프들이다. 이 측정 데이터가 S1~S10 각각의 대응하는 층 수를 의미하지는 않는다. XRD 측정에서는 Cu Kα1(1.540598Å), Kα2(1.544426) 선을 강도비 2:1로 혼합한 X선을 사용하였으며, 2θ는 20~50˚, step size는 0.016˚로 균일하게 하였고, 2theta(쎄타)-ω(오메가) 방식으로 측정하였다. 평행빔(Parallel beam) X선 optics 조사장치 및 Array 타입 검출기를 엑스선 회절 장비에 별도로 부착하여 사용하였다. 평행빔 X선 optics의 구체적인 예로 평행빔 X선 미러(Parallel beam X-ray Mirror) optics를 별도로 구비하여 사용하였다.9 is a graph showing XRD measurement data for S1 to S10. This measurement data does not mean the number of layers corresponding to each of S1 to S10. In XRD measurement, X-rays in which Cu Kα1 (1.540598Å) and Kα2 (1.544426) lines were mixed at an intensity ratio of 2: 1 were used. 2θ was uniformly set to 20-50 ° and step size was 0.016 °, and 2theta (Theta) ) -ω (omega) method. Parallel beam X-ray optics irradiator and Array type detector were separately attached to the X-ray diffraction equipment. As a specific example of parallel beam X-ray optics, parallel beam X-ray mirror optics were separately provided and used.
[도 9]의 (a)는 S1과 S2 두 시료를 비교 측정한 그래프인데, 두 그래프가 거의 일치하며 백그라운드 산란강도를 제외하고는 피크 형상이 전혀 발견되지 않았다. 1회 측정시 30~50분을 할애하여 충분히 오래 측정하였음에도 불구하고 피크가 관찰되지 않는다는 것은 흑연(기본 결정구조 3층)과 같이 (002) 피크를 형성하지 않음을 보여주는 결과이다.(A) of FIG. 9 is a graph comparing two samples of S1 and S2, and the two graphs are almost identical and no peak shape was found except for the background scattering intensity. Although the peak is not observed despite the measurement for 30 to 50 minutes in one measurement, the result shows that the (002) peak is not formed like graphite (three layers of the basic crystal structure).
[도 10]의 (b)에서부터 [도 10]의 (i) 까지는 (002) 피크가 조금씩 나오기 시작하며, 대략적으로 강도가 점점 커지는 경향을 보여준다. 이는 S3~S10 시료들의 정확한 층 수는 알 수 없지만 점점 두꺼운(즉, 층의 수가 증가하는) 그래핀 결정을 형성해 간다는 것을 알 수 있다. 이는 본 발명을 통하여 최초로 얻어진 가장 얇은 박막에 대한 결정학적 정보이다. From (b) of FIG. 10 to (i) of [FIG. 10], the (002) peak starts to come out little by little, and the intensity tends to increase. This indicates that the exact number of layers in S3 to S10 samples is not known, but forms increasingly thicker graphene crystals. This is the crystallographic information about the thinnest thin film first obtained through the present invention.
S3~S10 시료에 대한 (002) 피크 정보는 [도 10]의 테이블에 상세하게 나타내었다. 피크 피팅을 위해서 Baseline을 S2로 일정하게 하였다. 그리고 피크 피팅 함수로서 G 함수 및 L 함수를 이용하였고, [도 10]에는 이들을 구분하여 나타내었다.(002) peak information about the S3 ~ S10 samples are shown in detail in the table of FIG. Baseline was constant at S2 for peak fitting. In addition, the G function and the L function were used as peak fitting functions, and these are shown separately in FIG. 10.
(002) 피크로부터 얻어낼 수 있는 중요한 정보는 다음과 같다.Important information that can be obtained from the (002) peak is as follows.
(1) 그래핀 두께와 직접 연관되어 있는 FWHM(1) FWHM directly related to graphene thickness
(2) 그래핀 층간 간격을 구할 수 있는 d002(피크 센터인 2θ로부터 구함)(2) d 002 from which graphene interlayers can be determined (from peak center 2θ)
(3) 그래핀 두께{D1 = d002 × (NL-1) 또는 D2=d002 × (NL)}, 이때 NL은 그래핀 층 수(3) graphene thickness {D1 = d 002 × (N L -1) or D 2 = d 002 × (N L )}, where N L is the number of graphene layers
[도 10]는 G 함수 및 L 함수를 이용한 S3~S10 시료에 대한 FWHM 값, 피크 센터인 2θ 값들, 2θ로부터 구한 d002 값들이 나타내어져 있다.FIG. 10 shows FWHM values, 2θ values of peak centers, and d 002 values obtained from 2θ for S3 to S10 samples using G and L functions.
중요하게도, 그래핀 두께 즉 그래핀 층 수와 관련된 FWHM 데이터들은 S3→S4→S5로 갈수록 독립적이며 어떤 규칙을 가지고 줄어들고 있음을 알 수 있다.Importantly, the FWHM data related to graphene thickness, or graphene layer number, are independent from S3 → S4 → S5 and are decreasing with some rules.
S6 시료의 FWHM 값은 S5 시료와 거의 일치한다. S7, S8, S9 시료의 FWHM 값도 거의 일치된 값을 가지며, S10 시료는 독립적으로 가장 작은 FWHM 값을 가짐을 알 수 있다. 이 정보들은 매우 중요하다.The FWHM value of the S6 sample is almost identical to the S5 sample. The FWHM values of the S7, S8, and S9 samples also had almost identical values, and the S10 samples independently had the smallest FWHM values. This information is very important.
그 이유로서, 흑연처럼 그래핀 결정도 S3 시료에서 최초 (002) 피크 (FWHM: 4.663-5.06˚)가 약하나마 발견되는데(S1, S2는 관찰안 됨), 이때의 피크는 확실히 그래핀 3층의 정보이며, 흑연의 결정처럼 XRD로 측정 가능한 가장 얇은 그래핀 결정층(최소 층 수)은 3층이다.As a result, graphene crystals, like graphite, are found to have a slight initial (002) peak (FWHM: 4.663-5.06 °) in the S3 sample (S1 and S2 are not observed). For information, the thinnest graphene crystal layer (minimum number of layers) that can be measured by XRD, like crystals of graphite, is three layers.
S4 시료에서는 S3 시료와는 상대적으로 강도가 크며 FWHM이 독립적이며 예리한(FWHM: 3.207-3.310˚) 피크가 나타나는데 이는 확실히 주된 결정이 4층인 그래핀에 대한 정보이다(5층은 적층공정상 불가능함).In S4 sample, the intensity is relatively high compared to S3 sample, and FWHM is independent and sharp (FWHM: 3.207-3.310˚) shows peaks, which is certainly information about graphene whose main crystal is 4 layers (5 layers are impossible in the lamination process). ).
또한 S5 시료는 S4 시료와는 아주 다르게 매우 강도가 크며 훨씬 예리한 (FWHM: 1.798-1.84˚) 피크가 나타나는데 이는 확실히 주된 결정이 5층인 그래핀에 대한 정보이다(6층은 적층공정상 불가능함).In addition, the S5 sample is very strong and very sharp (FWHM: 1.798-1.84 °) peaks, unlike the S4 sample, which is certainly information about graphene whose main crystal is 5 layers (6 layers is impossible in the lamination process). .
S6 시료의 FWHM 값이 S5 시료 FWHM의 값과 거의 일치한다는 것은 S6의 적층공정이 S5 정도밖에 유효하지 못하다는 것을 반영하며, 즉 S6 시료는 5층 그래핀 결정에 대한 정보를 보여준다.The FWHM value of the S6 sample closely matches that of the S5 sample FWHM, reflecting that the stacking process of S6 is only as effective as S5, i.e., the S6 sample shows information about the 5-layer graphene crystal.
S7~S9 시료는 서로 비슷한 값을 가지며, 5층 그래핀과는 독립적이면서도 이론적인 모델처럼 비슷한 경향으로 FWHM이 작아지는데 이는 6층 그래핀을 반영하는 결과이다.Samples S7 to S9 have similar values, and are independent of five-layer graphene but have similar trends as the theoretical model, resulting in a smaller FWHM, reflecting six-layer graphene.
마지막으로 S10 시료는 가장 강한 피크강도와 6층 그래핀과 비교하여 1단계 정도 작아진 피크 강도를 보여주는데 이는 그래핀 7층에 대한 정보이다.Finally, the S10 sample shows the strongest peak intensity and the peak intensity reduced by about one step compared to the six-layer graphene, which is information on the seven graphene layers.
이에 대하여 [도 10] 테이블의 제일 우측편에 XRD 측정으로부터 S1~S10 시료에 대한 층 수 별 그래핀 결정들을 확정하여 정리하였다. On the right side of the table [Fig. 10] to determine the graphene crystals by layer number for the S1 ~ S10 samples from the XRD measurement was summarized.
[도 11]은 검량선을 그리기 위해 x축으로 이용 가능한 수치들을 정리한 표이다. [도 10]에서 평가된 그래핀 층 수 별 FWHM (°) 절대값들을 y축으로 할 때, x축은 그래핀 층 수(NL)로 할 수 있으며, 그래핀 두께(D)나 그래핀 두께의 역수(1/D)로 할 수도 있다. 여기서 그래핀 두께(D)는 원자 중심간 거리를 기준으로 한 분석대상 그래핀막의 두께(D1)나 원자의 최대 외경간 거리를 기준으로 한 분석대상 그래핀막의 두께(D2)로 구할 수 있다.FIG. 11 is a table summarizing the values available on the x-axis to draw a calibration curve. When the absolute values of FWHM (°) for each graphene layer evaluated in FIG. 10 are y-axis, the x-axis may be graphene layer (N L ), and graphene thickness (D) or graphene thickness It can also be set as the inverse (1 / D) of. Here, the graphene thickness (D) may be obtained from the thickness of the graphene film to be analyzed (D 1 ) based on the distance between atomic centers or the thickness of the graphene film to be analyzed (D 2 ) based on the maximum outer distance of atoms. have.
D1 = d002 × (NL-1) (이때 NL은 그래핀 층 수)D 1 = d 002 × (N L -1), where N L is the number of graphene layers
D2 = d002 × (NL) (이때 NL은 그래핀 층 수)D 2 = d 002 × (N L ), where N L is the number of graphene layers
이들에 대한 검량선 그래프들을 [도 12]의 (a), (b), (c)에 각각 나타내었다.Calibration curve graphs for these are shown in (a), (b) and (c) of FIG. 12, respectively.
빨간색선(red circled dotted, △로 표기)들은 L 함수 피팅 결과를 반영한 것이고 파란색선(blue triangle dotted, ○로 표기)들은 G 함수 피팅 결과를 반영한 것이다.Red circles (denoted △) reflect the L function fitting results and blue triangle dotted (○) reflect the G function fitting results.
그 외 다양한 형태의 검량선들이 가능하며, 그래핀 층간 간격 d002이 같은 층이라도 적층공정에 따라 약간씩 변할 수도 있으며, 고정된 값으로 흑연의 d002 값을 이용하더라도 에러 범위 내에서는 큰 문제가 없다([도 13] 참조).Various types of calibration curves are possible, and even if the graphene interlayer d 002 is the same, it may change slightly depending on the lamination process. Even if the d 002 value of graphite is used as a fixed value, there is no big problem within the error range. (See FIG. 13).
[도 12]의 (d) 그래프는 x축을 1/D로 하고 y축을 FWHM으로 하여 얻어낸 데이터([도 12]의 (c)에 해당하는 그래프)와 sherrer식에 의해 이론적으로 얻어낸 그래프를 비교한 데이터이다. 이론적 sherrer식은 결정이 커질수록 원점을 향한 완전한 직선 그래프가 된다. 반면 실험치인 경우 그래핀 층 수가 3, 4인 경우 직선에서 벗어난 경향을 보이는데 이는 2차원 결정인 3~4층의 그래핀이 일반적인 결정과는 다른 물성을 가지고 있음을 보여주는 매우 중요한 데이터이다.The graph (d) of FIG. 12 compares the data obtained by using the x-axis as 1 / D and the y-axis as FWHM (graph corresponding to (c) in FIG. 12) and the graph theoretically obtained by the sherrer equation. Data. Theoretically, the larger the crystal, the more complete the graph becomes toward the origin. On the other hand, in case of experimental values, 3 and 4 graphene layers show a tendency to deviate from the straight line. This is very important data showing that 3 to 4 layers of graphene, which are two-dimensional crystals, have different physical properties from general crystals.
그래핀 층수가 5, 6, 7인 경우 이론적 값들처럼 원점을 향한 직선거동을 보이는데 이 또한 매우 중요한 결과로서 미지 그래핀 시편의 두께가 13Å(5층) 근처이거나 이보다 큰 경우 이 직선을 검량선으로하여 그래핀 두께를 구할 수 있게 된다.In case of graphene layers of 5, 6 and 7, the linear behavior toward the origin is shown as the theoretical values. This is also very important. If the thickness of the unknown graphene specimen is near or larger than 13Å (5 layers), the straight line is used as the calibration curve. Graphene thickness can be obtained.
[도 12]의 (d)에 표시된 점선은 그래핀 5~7층에 대해 선형 피팅한 결과로서, 직선의 함수가 D1의 경우 y=22.358x+0.220(G 함수 피팅) 및 y=22.141x+0.191(L 함수 피팅)이다. D2의 경우 y=32.743x+0.062(G 함수 피팅) 및 y=32.427x+0.089(L 함수 피팅)이며, 이 때 y는 FWHM (°)이고 x는 1/D 이다. 또한 y축의 FWHM의 Degree(°) 값들은 적절하게 radian 등으로 변형시켜 사용할 수 있다.The dotted lines shown in (d) of FIG. 12 are linear fitting results for 5 to 7 layers of graphene, and y = 22.358x + 0.220 (G function fitting) and y = 22.141x when the function of the straight line is D 1 . +0.191 (L function fitting). For D 2 y = 32.743x + 0.062 (G function fitting) and y = 32.427x + 0.089 (L function fitting), where y is FWHM (°) and x is 1 / D. Also, degree (°) values of FWHM on the y-axis can be transformed into radian, etc. as appropriate.
그래핀 두께 혹은 층 수 이외에도 나노박막 및 나노결정립의 크기를 이들 검량선 들의 에러범위([도 10] 및 [도 11] 참조)를 포함한 기울기 및 이 때 얻어지는 y절편들의 범위 내에서 구 할 수 있다. 즉, 그래핀 층 수 5, 6, 7을 기준으로 직선의 검량선을 그릴 경우 오차범위 내에서 기울기가 14~40 정도이며, y절편은 -2~2 범위가 된다. 만일 층 수 3, 4, 5를 기준으로 에러범위를 정한 후 검량선을 그릴 경우 상기 값과는 전혀 다른 기울기와 절편을 갖는다.In addition to the graphene thickness or the number of layers, the size of the nano thin film and the nano grains can be obtained within the slope including the error range of these calibration lines (see FIGS. 10 and 11) and the y-intercepts obtained at this time. That is, when a straight calibration curve is drawn based on the number of graphene layers 5, 6, and 7, the slope is about 14-40, and the y-intercept is -2-2. If an error range is drawn based on the number of floors 3, 4, and 5, the slope and intercept are completely different from the above values.
따라서, 본 발명에서 [도 12]의 그래프 및 검량선의 에러범위를 정하기 위하여 중요한 점은 그래핀 층 수 별 FWHM의 에러를 정하는 것이다. 본 발명에서는 추가적인 시료들에 대한 측정 및 피팅 결과로부터 S3~S7 시료의 FWHM 에러들을 최대로 각각 ±1.5˚, 1.0˚, 0.5˚, 0.4˚, 0.4˚로 잡았으며, S5~S7의 선형 검량선의 최대 가능한 값으로서 기울기는 14~30, y절편은 -2~2로 하였다.Therefore, in the present invention, in order to determine the error range of the graph and the calibration curve of [Fig. 12], it is important to determine the error of FWHM for each graphene layer. In the present invention, the FWHM errors of the S3 to S7 samples were measured to ± 1.5 °, 1.0 °, 0.5 °, 0.4 °, and 0.4 °, respectively, from the measurement and fitting results of the additional samples. As the maximum possible value, the slope was 14 to 30 and the y-intercept was -2 to 2.
추가로 [도 13]에는 그래핀 3층~7층 전체에 대하여 직선이라는 가정하에서 최대로 가능한 영역의 기울기와 절편을 구하였다. 이를 위해서 최대 기울기를 갖는 Plot 1(y=82x-4.6) 직선과 최소 기울기를 갖는 Plot 2(y=12.6x+1.1) 직선을 정하고 이들 기울기와 y절편값이 절대적으로 벗어날 수 없는 검량선의 마지노선영역을 확정지었다. 이 때 기울기는 12~82 영역을 가지며, y절편은 1.12~-4.6영역을 가진다.In addition, in FIG. 13, the slope and intercept of the maximum possible area were determined under the assumption that the graphene was the straight line for the entire 3 ~ 7 layers of graphene. To do this, define a Plot 1 (y = 82x-4.6) straight line with the maximum slope and a Plot 2 (y = 12.6x + 1.1) straight line with the minimum slope, and the line of the calibration curve where these slopes and y-intercepts cannot absolutely escape. You have finalized the area. In this case, the slope has a region of 12 to 82 and the y-intercept has a region of 1.12 to -4.6.
다양한 에러 범위 내에서 가능한 검량선 영역을 지정하였지만, 본 연구내용은 [도 12]에서 그래핀 층 수 별 절대적인 FWHM을 보여준다. 이들을 비교데이터로 하여 미지의 그래핀을 측정할 경우 이들 데이터와 비교 분석하여 그래핀층 수를 결정할 수 있다. 일 예로 다층 막 그래핀 결정을 성장시킨 후 얻어낸 XRD(002) 피크에 대한 FWHM의 값이 2.5˚라는 값이 나오면 본 발명의 결과로부터 이 값은 그래핀 4층(3.207˚) 및 5층(1.844˚) 값의 절반에 해당하므로 4.5층이라는 결론을 가진다. 현실적으로 4.5층이라는 그래핀 결정은 없으나 여러 층이 존재하는 결정들의 평균값이 4.5층이라는 매우 중요한 정보를 제공한다. 현재까지 이런 분석방법은 제공되지 못하였다.Although the calibration curve region was specified within various error ranges, the present study shows the absolute FWHM by the number of graphene layers in [FIG. 12]. When the unknown graphene is measured using these data as comparative data, the number of graphene layers may be determined by comparative analysis with these data. As an example, if the value of FWHM for the XRD (002) peak obtained after growing the multilayer film graphene crystal is 2.5 °, the value of the graphene is 4 layers (3.207 °) and 5 layers (1.844). Since it is half of the value, it is concluded that it is 4.5 stories. In reality, there is no graphene crystal of 4.5 layers, but it provides very important information that the average value of crystals having multiple layers is 4.5 layers. To date, no such method has been provided.
XRD 피크 해석에 잘 맞는 프로그램이 있으면, (002) 피크 피팅으로 부터 피크들을 분리한 후 분리된 피크의 반가치 폭을 평가한 후(본 발명과 비교하여) 그래핀 층 수 분포도 알아낼 수 있다. 일예로 상기 시료에 대하여 단일 피크피팅을 수행하지 않고 다중 피크들이 중첩된 것을 분리한 후 각각의 FWHM에 대한 층 수 정보를 제공한 후, 피팅 피크 면적으로서 각각의 층에 대한 결정량을 도출하여, 3층이 30%, 4층이 40%, 5층이 30%처럼 나타낼 수 있다. 이와 같이 할 수 있는 것은 또 다른 본 발명의 효과라 할 수 있다.If there is a program well suited to XRD peak analysis, the peaks from the (002) peak fitting can be separated and the half value width of the separated peaks evaluated (compared to the present invention) to determine the graphene layer number distribution. For example, after separating the overlapping multiple peaks without performing a single peak fitting on the sample, providing the number of layers information for each FWHM, and then deciding the crystal quantity for each layer as a fitting peak area, The third layer can be represented as 30%, the fourth layer as 40%, and the fifth layer as 30%. What can be done in this way is another effect of this invention.
또한 본 시험과 비슷하거나 더 좋은 조건에서 XRD 측정 실험을 수행하였는데 (002) 피크가 관찰되지 않으면 그래핀의 층 수가 1~2층임을 의미한다. In addition, XRD measurement experiments were carried out under conditions similar to or better than those in this test, and if no (002) peak was observed, it means that the graphene had one or two layers.
본 발명의 평행빔 엑스선 소스, 검출기, 시편의 회전 각도는 x, y, z 축으로 회전이 모두 가능할 수 있다. 현 기술로는 이 모든 회전이 가능하지만 극한 박막을 분석할 경우 반드시 보충이 되어야만 하는 기술이다.The angle of rotation of the parallel beam X-ray source, detector, and specimen of the present invention may be all rotatable in the x, y, and z axes. All of these rotations are possible with current technology, but they must be replenished when analyzing extreme thin films.
[실시예 5]Example 5
민감한 S3~S5 샘플에 대한 다양한 비교실험을 하였는데, 실험결과는 [표 1]에 나타내었다.Various comparative experiments were performed on sensitive S3 ~ S5 samples, and the experimental results are shown in Table 1.
표 1
장치기술 측정조건 샘플의 피크 강도 비교
S3 S4 S5
평행빔 X선 + Array 형 검출기 5 ~ 55 (도 1) 100 100 100
3 ~ 5 0 15 20
55 ~ 58 0 10 14
습도 67 ~ 70% 100 90 92
습도 70 ~ 73% 0 24 25
평행빔 X선 + Normal 형 검출기 상온 및 습도 40% 45 65 75
focused beam X선 + Array 형 검출기 상온 및 습도 40% 0 0 0
focused beam X선 + Normal 형 검출기 상온 및 습도 40% 0 0 0
Table 1
Technology Measuring conditions Peak Intensity Comparison of Samples
S3 S4 S5
Parallel Beam X-ray + Array Detector 5 to 55 (Fig. 1) 100 100 100
3 to 5 0 15 20
55 to 58 0 10 14
Humidity 67 ~ 70% 100 90 92
Humidity 70-73% 0 24 25
Parallel Beam X-ray + Normal Detector Room temperature and humidity 40% 45 65 75
focused beam X-ray + Array type detector Room temperature and humidity 40% 0 0 0
focused beam X-ray + normal detector Room temperature and humidity 40% 0 0 0
[도 9]의 3층에서 7층에 대한 정보는 엑스선 회절 장치에 (1) 평행빔 엑스선 조사기와 (2) Array형 검출기가 동시에 작동하였을 때의 그래프이다.Information on the third to seventh layers in FIG. 9 is a graph when (1) the parallel beam X-ray irradiator and (2) the array type detector are simultaneously operated in the X-ray diffraction apparatus.
S3~S5 민감한 샘플들의 (002) 피크 강도를 100으로 하여 장치 기술, 측정 조건을 변화시키면서 비교 하였다. [표 1]에서 보는것처럼 상기 2가지 장치 기술에 측정온도가 5~55℃ (278~328°K)인 경우는 민감한 그래핀이라 할지라도 피크 강도의 변화는 거의 없음을 알 수 있다(정확히 표현하면 5~8℃ 범위 및 45~50℃ 범위는 약 2% 정도의 변화를 보여 엄밀한 실험을 할 경우 8~45℃ 범위 내가 바람직하다. 그러나 통상적인 실험에서 상기 온도 범위를 이용하는 데는 큰 문제가 없다).The (002) peak intensity of the S3 to S5 sensitive samples was set to 100 and compared with changing device technology and measurement conditions. As shown in [Table 1], when the measurement temperature is 5 to 55 ° C (278 to 328 ° K) for the above two device technologies, even the sensitive graphene shows little change in peak intensity (exactly expressed). The range of 5 ~ 8 ℃ and 45 ~ 50 ℃ shows about 2% change, so it is preferable to use 8 ~ 45 ℃ for the rigorous experiment, but there is no big problem in using the temperature range in the normal experiment. ).
그러나, 측정 시편의 온도가 5℃ 이하 혹은 55℃ 이상일 경우 피크가 없어지거나 급격한 감소를 보이는데 이는 장시간 측정시 초박막 그래핀이 변할 수 있음을 보여주는 매우 중요한 데이터이다. 또한 상온일지라도 습도가 70% 이상되면 초박막 그래핀의 (002) 피크가 사라지거나 급격한 감소를 보인다. 이와 같은 온도변화 (기계열, 열름철 날씨)나 습도 영역을 통상적인 엑스선 회절실험에서 흔히 발생할 수 있는 조건이며, (002) 피크가 얻어지지 않거나 매우 약화될 경우 잘못된 해석을 내릴 수 있게 된다. 이와 같은 현상은 기존 시편에서는 발생하지 않았으며 매우 얇은 그래핀에서 처음 발견되는 현상이다.However, if the temperature of the test specimen is less than 5 ℃ or more than 55 ℃ the peak disappears or shows a sharp decrease, which is very important data showing that the ultra-thin graphene may change during long time measurement. In addition, even at room temperature, when the humidity is 70% or more, the (002) peak of the ultra-thin graphene disappears or shows a sharp decrease. Such temperature changes (mechanical heat, hot weather conditions) or humidity ranges are a common condition in conventional X-ray diffraction experiments. If (002) peaks are not obtained or become very weak, misinterpretation may occur. This is not the case in conventional specimens and is the first to be found in very thin graphene.
[표 1]에서는 일반적인 나노박막에서 많이 분석하고 있는 focused beam X-선 조사기와 Normal type 검출기를 비교 실험하였는데, focused beam X-선 조사기를 사용할 경우 S3~S5 샘플의 피크들이 모두 관찰되지 않는 놀라운 사실을 발견하였다. 이는 투과력이 좋은 엑스선이 포커스(집광) 되어 대부분 그래핀 막을 투과하기 때문인 것으로 해석이 되며, 기존 나노박막 분석에서는 발생하지 않았으며 매우 얇은 그래핀에서 처음 발견되는 현상이다.In Table 1, we compared the focused beam X-ray irradiator and the normal type detector, which are frequently analyzed in the general nano-thin film. When using the focused beam X-ray irradiator, all the peaks of the S3 to S5 samples were not observed. Found. It is interpreted that X-rays having good transmittance are focused (condensed) and mostly penetrate the graphene film. This is not the case in the existing nano thin film analysis and is the first phenomenon found in very thin graphene.
또한 패럴빔 엑스선 조사기에 검출기가 Normal 인 경우 피크가 나오지 않거나 약화된다([표 1] 참조).In addition, when the detector is normal in the parallax X-ray irradiator, the peak does not come out or is weakened (see [Table 1]).
따라서 본 발명에서는 그래핀 초박막의 층 수가 1~10층인 경우 패럴빔 엑스선 빔의 사용은 필수적이며, Array 타입 검출기는 측정의 신뢰도를 높이는 기능을 한다. 또한 아무리 측정 장치 조건이 좋더라도 반드시 측정 조건으로서 온도가 5~45℃(278~328°K) 및 습도 70% 미만으로 해야 한다.Therefore, in the present invention, the use of a parallel beam X-ray beam is essential when the number of layers of graphene ultra thin films is 1 to 10, and the array type detector functions to increase the reliability of the measurement. In addition, no matter how good the conditions of the measuring device, the temperature must be 5 ~ 45 ℃ (278 ~ 328 ° K) and less than 70% humidity as the measurement conditions.
5℃ 이하 및 55℃ 이상의 온도와 습도 70% 이상에서의 극한 그래핀 박막의 변화는 그래핀 층 간 매우 약한 반데르발스결합력으로 설명할 수 있다. H2O 물분자의 흡착은 통상적으로 강력하여 그래핀 주변의 수분은 그래핀 표면에 흡착되고 일부 물분자는 약한 그래핀 층 사이를 침투하여 그래핀의 결정성을 약화시키고 낮은 온도와 높은 온도는 이들 흡착된 물의 응집성 (부피가 커짐)과 분자단위 진동에 영향을 주어 결정성이 약화되는 것으로 해석할 수 있다.Changes in the extreme graphene thin film at temperatures below 5 ° C. and above 55 ° C. and humidity above 70% can be explained by very weak van der Waals bonding forces between graphene layers. The adsorption of H 2 O water molecules is typically strong, so that the water around the graphene is adsorbed on the graphene surface, and some water molecules penetrate between the weak graphene layers, weakening the crystallinity of the graphene, It can be interpreted that the crystallinity is weakened by affecting the cohesiveness (larger volume) and molecular vibration of the adsorbed water.
[실시예 7]Example 7
[도 9]의 S7인 경우 평행빔 엑스선을 그래핀 시료에 조사하며 검출기로 회절된 엑스선을 검출하는 측정방법이 ω(오메가)-2theta(쎄타) 일 경우 두가지 방법이 가능하다. 즉, 입사각을 고정하는 경우와 회전시키는 경우이다. 본 발명에서는 실리콘 웨이퍼 일부 결정면이 그래핀 (002) 피크와 일부간섭을 일으키는 것으로 파악을 하였다. 별도로 구비된 4층 그래핀 시료를 일반적인 ω(오메가)-2theta(쎄타)로 측정 하였을 경우 상대적으로 강도가 매우 큰 실리콘 웨이포 피크에 묻여 그래핀 (002) 피크의 관찰이 쉽지 않았다. 이를 해결하기 위하여 다음 [조사각 도출식]에 따라 도출된 각도로 평행빔 엑스선 조사각도를 고정하였다. 이렇게 하여 실리콘 피크는 나오지 않게 하고 그래핀 (002) 피크만 얻어낼 수 있었다.In the case of S7 of FIG. 9, two methods are available when the beam X-ray is irradiated to the graphene sample and the X-ray diffracted by the detector is ω (omega) -2theta (theta). In other words, the incident angle is fixed and rotated. In the present invention, it was found that some crystal surfaces of the silicon wafer cause some interference with the graphene (002) peak. When a separate four-layer graphene sample was measured with a typical ω (omega) -2theta (theta), it was not easy to observe the graphene (002) peak because it was buried in a relatively strong silicon wave peak. To solve this problem, the parallel beam X-ray irradiation angle was fixed at the angle derived according to the following [Derivation angle derivation equation]. In this way, the silicon peak was suppressed and only the graphene (002) peak was obtained.
[조사각 도출식][Derivation angle of expression]
X선 조사각 = (2θ(hkl)÷2)±1˚X-ray irradiation angle = (2θ (hkl) ÷ 2) ± 1˚
2θ(hkl) : 특정 밀러지수를 갖는 기준 그래핀 결정면의 피크 센터의 회절각2θ (hkl): diffraction angle of peak center of reference graphene crystal plane with specific Miller index
[실시예 8]Example 8
[도 13]은 GI SAXS법을 이용하여 찾아낸 층 수 7의 그래핀의 (002)피크가 아닌 또 다른 (hkl) 결정면에 대한 피크를 나타낸 그래프이다(2θ=42.525°). 이 피크는 통상적인 방법에서는 찾을 수 없다. 박막 수직면에 제공되는 결정면이 아니기 때문이다. 결정 수직면 이외에도 결정 수평면 xy면에 다양한 피크가 존재하며, 이들을 찾기 위해서는 GI SAXS법이 필요하다. 본 발명에서는 이 방법을 이용하여 7층 그래핀의 (002) 결정면 이외의 피크를 찾아내었다. 아직 (hkl) 지수를 정하지는 못하였지만, 이 피크에 대해서도 본 발명의 원리를 그대로 적용할 수 있다(d(hkl) 및 FWHM 이론 참조). 또한 GI SAXS 법을 통하여 또 다른 (hkl) 결정면을 찾을 예정이지만 시간이 너무 오래걸리는 단점이 있다. 그러나 최신 2차원 검출기를 가지는 GI SAXS 즉, 2D GI SAXS 장치를 이용하면 짧은 시간내에 그래핀 xy결정면의 피크들을 찾을 수 있고, 그래핀 층 수별 결정정보(결자상수)들 및 두께 정보에 대한 좀 더 정확한 정보들을 얻어낼 수 있다.FIG. 13 is a graph showing peaks for another (hkl) crystal plane instead of the (002) peak of graphene of layer number 7 found using the GI SAXS method (2θ = 42.525 °). This peak cannot be found by conventional methods. This is because it is not a crystal plane provided on the thin film vertical plane. In addition to the crystal vertical plane, various peaks exist on the crystal horizontal plane xy plane, and the GI SAXS method is required to find them. In the present invention, a peak other than the (002) crystal plane of the seven-layer graphene was found using this method. Although the (hkl) index has not yet been determined, the principle of the present invention can be applied to this peak as it is (see d (hkl) and FWHM theory). In addition, the GI SAXS method will find another (hkl) facet, but it takes a long time. However, using the GI SAXS with the latest two-dimensional detector, that is, the 2D GI SAXS device, it is possible to find the peaks of the graphene xy crystal plane in a short time, and to obtain more information about the determination information (decision coefficient) and thickness information for each graphene layer number. Accurate information can be obtained.
GI SAXS 법은 그래핀 (002) 피크보다 강도가 매우 약한 또다른 피크를 찾아낼 수 있을 정도의 강력한 방법이다. 따라서 본 발명에서 GI SAXS 법은 그래핀의 (002) 면을 찾을 경우에도 중요하게 이용될 수 있다. 좀 더 나아가 2차원 검출기가 장착된 2D GISAXS는 더욱 간단하게 그래핀 피크들을 O아낼 수 있다. 이와 같은 본 발명의 원리는 향후 개발될 3차원 (혹은 2.5차원: 부분적인 공간 커버)) 검출기 개념에도 적용이 가능하다.The GI SAXS method is powerful enough to find another peak that is much weaker than the graphene (002) peak. Therefore, in the present invention, the GI SAXS method may be important when finding the (002) plane of graphene. Further, 2D GISAXS with a two-dimensional detector can more easily omit graphene peaks. This principle of the present invention is also applicable to the concept of a three-dimensional (or 2.5-dimensional: partial space cover) detector to be developed in the future.
[도 14]는 3층 내지 10층(S3~S10) 그래핀 결정면에 대한 록킹커브(Rocking curve) 그래프이다. x축은 오메가(Omega)의 각도(°)이다. 이 록킹커브는 (hkl) 결정면의 배향성이 어떤지 (tilting 등), 얼마만큼 기울어져 있는지를 알려주는 매우 중요한 측정방법이다. 록킹커브를 측정할 때 검출기를 다음 [검출각 도출식]에 따라 도출된 각도로 검출기의 각도를 고정하였다. 이렇게 한 후 오메가 각도를 미세하게 +에서 -로 변화시킨면서 엑스선 회절 강도를 측정하였다.FIG. 14 is a graph of rocking curves for 3 to 10 layer (S3 to S10) graphene crystal surfaces. FIG. The x-axis is the angle in omega (°). This locking curve is a very important measuring method that tells the orientation of the crystal plane (hkl) and how much it is tilted. When measuring the locking curve, the detector was fixed at an angle derived from the following detection angle derivation equation. After doing this, the X-ray diffraction intensity was measured while slightly changing the omega angle from + to-.
[검출각 도출식][Detecting angle derived expression]
검출기 조사각 = (2θ(hkl))±1˚Detector irradiation angle = (2θ (hkl) ) ± 1˚
2θ(hkl) : 특정 밀러지수를 갖는 기준 그래핀 결정면의 피크 센터의 회절각2θ (hkl): diffraction angle of peak center of reference graphene crystal plane with specific Miller index
그래핀 (002) 결정면에 대한 록킹커브를 [도14]에 나타내었다. [도14] 피크의 중심 값이 [도 9]에 나타난 그래핀 (002) 결정면의 피크 2θ의 1/2이 된다. 10층 그래핀(S10) 록킹커브(Rocking curve) 그래프의 피크 중심선을 기준으로 하였을 경우, 각 층 그래핀 결정의 결정 배향 중심 및 분포가 달라지며([도 14]의 피크들은 결정 배향 분포 함수임), 각 중심에서 가장 자리로 갈수록 강도가 낮아지는데, 이는 피크 중심이 결정의 xy축과 일치하는 평면(0°)에 위치한 결정면의 기울기(tilt) 정도를 나타낸다. 즉 [도 14]의 x축을 다시 그릴 경우, 피크 센터는 0°, 좌측부는 마이너스 각도로 기울어진 각도, 우측부는 플러스 각도로 기울어진 각도를 나타내며 이들 값에 대한 y 값, 즉 피크 강도는 각각의 각도에 존재하는 그래핀 (002) 결정면들의 분포함수를 나타낸다. 따라서, 본 발명에서는 층 수별 2차원 그래핀들이 완벽한 2차원 평면에 위치하지 않고 약간 너울대는 형태(+, 0, - 분포)로 존재하고 있음을 보여주는 최초의 XRD 정보도 제공하고 있다.The locking curve for the graphene (002) crystal plane is shown in FIG. The central value of the peak becomes 1/2 of the peak 2θ of the crystal plane of the graphene (002) shown in FIG. Based on the peak center line of the 10-layer graphene (S10) rocking curve graph, the crystal orientation center and distribution of each layer graphene crystal are different (peaks of FIG. 14 are a function of the crystal orientation distribution). Intensity decreases from the center to the edge, indicating the tilt of the crystal plane in the plane (0 °) where the peak center coincides with the xy axis of the crystal. That is, when the x-axis of FIG. 14 is drawn again, the peak center represents 0 °, the left portion is inclined at a negative angle, and the right side is inclined at a plus angle. The y values for these values, that is, the peak intensity are respectively The distribution function of graphene (002) crystal planes present at an angle is shown. Accordingly, the present invention also provides the first XRD information showing that the two-dimensional graphenes by number of layers are not located in a perfect two-dimensional plane, but exist in a slightly clumped form (+, 0,-distribution).
또한 이 정보를 바탕으로 기판의 간섭을 없애기 위하여 앞서 설명한 고정 입사각 (2θ÷2)±1˚는 Rocking curve의 피크센터 Omega를 기준으로 다시 표현이 가능한데 Omega±1˚로 표기될 수 있다.Also, based on this information, the fixed incident angle (2θ ÷ 2) ± 1 ° described above can be re-expressed based on the peak center omega of the rocking curve, which can be expressed as omega ± 1 °.
[실시예 9]Example 9
표 2
장치기술 측정조건 6층 그래핀의 d002(층간간격)
평행빔 X선+Array 형 검출기 상온 100
200도 96
400도 92
600도 99
800도 105
-50도 98
-100도 96
-200도 94
TABLE 2
Technology Measuring conditions D 002 of 6-layer graphene (interval)
Parallel Beam X-ray + Array Detector Room temperature 100
200 degrees 96
400 degrees 92
600 degrees 99
800 degrees 105
-50 degrees 98
-100 degrees 96
-200 degrees 94
5℃ 이하 및 55℃ 이상의 온도조건과 및 70% 이상 습도조건에서의 좋지 않은 효과를 극대화시켜 극한 분석 박막장치에 진공열처리 시스템과 액체 질소와 같은 냉각시스템을 둘 수 있다. [표 2]에서 보는 것처럼 6층 그래핀의 경우 진공 열처리 할 경우 d002 그래핀 면간간격의 변화 거동을 관찰 할 수 있다. 온도가 상승할수록 면간간격이 줄어들다가 커지는데 이는 어닐링효과에 의한 결정품질의 상승 및 더 높은 온도에서의 분자 진동에 의한 면간간격 증가로 해석될 수 있다.By maximizing the adverse effects at temperatures below 5 ° C and above 55 ° C, and above 70% humidity conditions, extreme analytical thin film devices can be equipped with vacuum heat treatment systems and cooling systems such as liquid nitrogen. As shown in [Table 2], the change behavior of the d 002 graphene interplanar spacing can be observed in the case of 6-layer graphene vacuum treatment. As the temperature increases, the interplanar spacing decreases and increases, which can be interpreted as an increase in the crystal quality due to the annealing effect and an increase in the interplanar spacing due to molecular vibration at higher temperatures.
[표 2]에는 또한 액체질소를 이용한 냉각실험에서도 극한 그래핀 박막의 면간 간격변화를 연구할 수 있다. 이 때 면간 간격 변화는 그래핀 분자의 열적 진동에너지 감소와 흡차된 물분자의 회합, 고상변화 등의 효과로 설명할 수 있다.Table 2 also shows the variation of interplanar spacing of extreme graphene films in cooling experiments using liquid nitrogen. In this case, the change in the interplanar spacing may be explained by the effect of reducing the thermal vibration energy of the graphene molecules, the association of the absorbed water molecules, and the solid phase change.
[실시예 10]Example 10
[도 10] 내지 [도 12]에 그래핀 층수별 FWHM을 나타내었으며 이를 레퍼런스로 하여 미지 그래핀의 층 수를 평가할 수 있다. 이와 같은 원리는 기존 극한 박막에서는 없었던 기술이다. 일예로 다층 막 그래핀 결정을 성장시킨 후 얻어낸 XRD (002)피크에 대한 FWHM의 값이 2.5˚라는 값이 나오면 본 연구의 결과로부터 이 값은 그래핀 4층 (3.207˚) 및 5층 (1.844˚) 값의 절반에 해당하므로 4.5층이라는 결론을 가진다. 이론적으로 4.5층이라는 그래핀 결정은 없으며 여러층이 존재하는 결정들의 평균값이 4.5층이라는 매우 중여한 정보를 제공한다. 현재까지 이런 분석 방법은 제공되지 못하였다. 이와 같은 원리는 서론에서 언급되었던 다양한 그래핀류(종류, 분류명, 도핑, 산소 및 황 성분, 표면 모디파이 등)에 똑같이 적용할 수 있다10 to 12 show FWHM for each graphene layer, and the number of layers of the unknown graphene may be evaluated using this as a reference. This principle is a technology that did not exist in the existing extreme thin film. For example, if the value of FWHM for the XRD (002) peak obtained after the growth of multilayer film graphene crystals is 2.5 °, the value of the graphene is 4 layers (3.207 °) and 5 layers (1.844). Since it is half of the value, it is concluded that it is 4.5 stories. Theoretically, there is no graphene crystal of 4.5 layers, and it is very important that the average value of crystals having multiple layers is 4.5 layers. To date, no such analysis has been provided. The same principle can be applied to various graphenes mentioned in the introduction (type, classification, doping, oxygen and sulfur components, surface modifiers, etc.).
[실시예 11]Example 11
[도 9]의 S3 시편의 크기(1cm×1cm)에서 가로 및 세로의 크기를 각각 절반(0.5cm×0.5cm) 으로 한 경우 피크가 완전히 사라짐을 알 수 있었다. S5 시편인 경우(1cm×1cm)를 가로 및 세로의 크기를 0.3cm×0.3cm로 할 경우 피크가 완전히 사라짐을 알 수 있었다. 즉 시편의 크기가 0.3~0.5cm×0.5cm 이상이 되어야 최소 두께를 갖는 극한 박막의 결정 피크를 얻어낼 수 있음을 알아내었다. 시편의 크기는 클수록 좋지만 본 발명에서 바람직한 시편의 크기는 최소 0.5cm×0.5cm 이상이 바람직하다 (그래핀 층 수가 커질수록 시편의 크기는 작아도 됨).In the size (1 cm × 1 cm) of the S3 specimen of FIG. 9, the peaks disappeared completely when the horizontal and vertical sizes were set to half (0.5 cm × 0.5 cm), respectively. In the case of the S5 specimen (1cm × 1cm), the peak disappears completely when the horizontal and vertical sizes are 0.3cm × 0.3cm. That is, it was found that the crystal peak of the ultimate thin film having the minimum thickness could be obtained only when the size of the specimen was 0.3 to 0.5 cm × 0.5 cm or more. The larger the size of the specimen, the better. However, the preferred size of the specimen in the present invention is preferably at least 0.5 cm × 0.5 cm (the larger the graphene layer, the smaller the specimen).
[실시예 12]Example 12
[도 10]의 S3 시편 측정시 사용된 omega-2theta 모드를 일반 분말형 XRD에서 사용하는 Thrta-2Theta 측정 방법으로 측정한 한 결과 (002) 피크는 관찰이 되지 않았다. 따라서 본 발명에서는 다양한 장치 옵티스가 결합되고 환경적인 측정조건 및 상기 측정 방법이 동시에 결합되어야 만이 가장 얇은 극한 박막이 3층 그래핀의 결정학적 정보를 얻을수 있음을 보여준다.As a result of measuring the omega-2theta mode used when measuring the S3 specimen of FIG. 10 by the Thrta-2Theta measuring method used in the general powder type XRD, the (002) peak was not observed. Therefore, the present invention shows that the thinnest ultimate thin film can obtain crystallographic information of three-layer graphene only when various device opti- ties are combined, and environmental measurement conditions and the measurement methods are simultaneously combined.
[실시예 13]Example 13
[도 10]의 S10 시편에 이용되었던 CVD 그래핀을 8mm×8mm(가로×세로) 비어있는 금속홀더에 전사시킨 후 엑스선 분석장치 중앙부에 위치시키고, 엑스선 조사장치를 시편부 기준으로 좌측 상단부 검출기를 우측 하단부로 보낸 후 조사된 엑스선이 그래핀이 놓여있고 기판이 비어있는 8mm×8mm 지역을 투과시킨 후 omega-2theta로 측정하여 투과율 감소 및 (002) 결정면의 FWHM을 얻어내었다. 그래핀 시편 자체의 흡수 및 산란에 의한 투과율 감소는 약 1~3.5로 나타났다. (002)결정면의 FWHM을 분석한 결과 앞의 그래핀 레퍼런스와 비교한 결과 층수가 5.8로 나타났다. 이와 같은 실험은 통상적으로 분석하는 엑스선 반사법, 엑스선 산란법, 엑스선 형광분석법, 엑스선 회절법과는 달리 투과에 의한 엑스선 투과 분석법, 투과에 의한 엑스선 흡수법, 투과에 의한 엑스선 회절법이 극한 박막 그래핀에서 가능함을 보여주고 있다.The CVD graphene used for the S10 specimen of FIG. 10 was transferred to an 8 mm × 8 mm (width × length) empty metal holder, and then placed in the center of the X-ray analyzer, and the X-ray irradiation device was placed on the upper left detector based on the specimen. The X-rays irradiated after passing through the lower right side penetrated the 8 mm × 8 mm region where the graphene was placed and the substrate was empty, and measured by omega-2theta to obtain transmittance decrease and FWHM of the (002) crystal plane. The decrease in transmittance due to absorption and scattering of the graphene specimen itself was about 1 to 3.5. Analysis of the (002) crystal plane FWHM showed that the number of layers was 5.8 when compared with the graphene reference. Unlike the conventional X-ray reflection method, X-ray scattering method, X-ray fluorescence method, and X-ray diffraction method, such experiments are performed in thin film graphene where X-ray transmission analysis by transmission, X-ray absorption by transmission, and X-ray diffraction by transmission are used. It shows the possibility.
[실시예 14]Example 14
그래핀 산화물을 제조하는 방법으로서 Modified Hummers 방법을 비롯한 Hummers법, Brodie법, Hofman&Frenzel법, Hamdi법, Staus법 등이 사용될 수 있다. 본 발명에서는 Modified Hummers 방법을 사용하였다. 구체적인 실시예로서, 마이크로 흑연 분말 50 g과 NaNO3 40g을 ~200 mL H2SO4 용액에 넣고 냉각시키면서 KMnO4 ~250g을 1시간에 걸쳐 천천히 넣어 준다. 그 후 4-7% H2SO4 5L을 1시간에 걸쳐 천천히 넣어주고 H2O2을 넣어준다. 그 후 원심 분리하여 침전물을 3%H2SO4-0.5%H2O2 및 증류수로 씻어주면 황갈색의 그라핀 산화물 수계 슬러리가 얻어졌다.As a method for producing graphene oxide, a Hummers method, a Brodie method, a Hofman & Frenzel method, a Hamdi method, a Staus method, etc., including a Modified Hummers method, may be used. In the present invention, the Modified Hummers method was used. As a specific example, 50 g of micro graphite powder and 40 g of NaNO 3 were added to a solution of ˜200 mL H 2 SO 4 , and slowly added KMnO 4 to 250 g over 1 hour while cooling. Then add 4-7% H 2 SO 4 5L slowly over 1 hour and H 2 O 2 . After centrifugation, the precipitate was washed with 3% H 2 SO 4 -0.5% H 2 O 2 and distilled water to give a yellowish brown graphene oxide aqueous slurry.
이를 PET 위에 두께 300nm로 코팅한후 150도에서 건조한 후 박리시켰다. 박리시킨 그래핀 막을 8mm×8mm(가로×세로) 비어있는 금속홀더에 얹힌후 그 위에 물리적 고정법을 사용하여(덮개를 덮은 후 나사조임) 고정시킨 후 실시예 13처럼 엑스선 분석장치를 설정한 후 같은 조건으로 분석하였다. 그래핀 시편 자체의 흡수 및 산란에 의한 투과율 감소는 약 20~25로 나타났다. (002) 결정면은 2θ=12도 근처에 관찰이 되었다.It was coated on PET with a thickness of 300 nm, dried at 150 degrees, and then peeled off. The exfoliated graphene film was placed on an 8 mm x 8 mm (horizontal x vertical) empty metal holder, and then fixed by using a physical fixation method (covered and screwed), and then the X-ray analyzer was set up as in Example 13. The conditions were analyzed. The decrease in transmittance due to absorption and scattering of the graphene specimen itself was about 20-25. The (002) crystal plane was observed near 2θ = 12 degrees.
또한 상기 홀더 근처에 IR 램프에 의하여 그래핀 시편이 국부적으로 열처리될 수 있도록 열선을 조사하였다. 10분 후 온도가 400℃ 근처까지 도달하였는데, 이때 엑스선 투과율 감소 (혹은 흡수율의 증가)는 10~15로 높아졌음을 알수 있었다. 또한 2θ=22도 근처로서 매우 큰 변화가 있음을 보여준다. 이는 그래핀 산화물이 그래핀으로 열환원되면서 두께가 얇아지고 (투과율 감소)고 층간 간격이 좁아지는 것으로 해석이 된다. 열환원된 그래핀 (002) 결정면의 FWHM을 조사해본 결과 층 수가 약 6.4로 밝혀졌다. 이는 그래핀 분말 혹은 그래핀 분산액에 들어 있는 그래핀들의 층 수가 1~10층이며 본발명의 원리가 적용됨을 알 수 있고, 단지 시편의 두께는 이들 그래핀이 단순 적층되어 있음을 보여준다. 따라서 본 발명은 CVD 그래핀에서는 층 수가 1~10층이며, 그래핀 분말인 경우에서는 한 개의 그래핀에서 층 수가 1~10층임을 의미한다. 또한 이 실험은 그래핀 분말 혹은 그래핀 산화물들이 통상적으로 분석하는 엑스선 반사법, 엑스선 산란법, 엑스선 형광분석법, 엑스선 회절법과는 달리 투과에 의한 엑스선 투과 분석법, 투과에 의한 엑스선 흡수법, 투과에 의한 엑스선 회절법이 극한 박막 그래핀에서 가능함을 보여주고 있다.In addition, the heating wire was irradiated so that the graphene specimen can be locally heat treated by an IR lamp near the holder. After 10 minutes, the temperature reached near 400 ° C, where the decrease in X-ray transmittance (or increase in absorption) was increased to 10-15. It is also shown that there is a very large change in the vicinity of 2θ = 22 degrees. This is interpreted as the graphene oxide is heat-reduced to graphene, resulting in thinner thickness (reduced transmittance) and narrower interlayer spacing. Examination of the FWHM of the heat-reduced graphene (002) crystal plane revealed that the number of layers was about 6.4. It can be seen that the graphene powder or graphene contained in the graphene dispersion is 1-10 layers and the principle of the present invention is applied, only the thickness of the specimen shows that these graphene is simply stacked. Therefore, the present invention means that the number of layers in the CVD graphene is 1 to 10 layers, in the case of graphene powder means that the number of layers in one graphene is 1 to 10 layers. Also, unlike the X-ray reflection method, X-ray scattering method, X-ray fluorescence method, and X-ray diffraction method, which is commonly analyzed by graphene powder or graphene oxide, X-ray transmission analysis by transmission, X-ray absorption by transmission, X-ray by transmission It is shown that diffraction is possible for extreme thin graphene.
[실시예 15]Example 15
화학적 환원방법을 구체적으로 살펴보면 3% 그래핀 산화물 슬러리 2g에 증류수 100ml를 넣어서 잘 분산 시킨 후 히드라진 수화물(hydrazine hydrate) 1ml를 넣고 100℃에서 3-24시간 환원 처리한다 검은색으로 환원된 그래핀 들은 거름종이로 걸러 물과 메탄올을 이용하여 세척해준다. 하이드라이진 수화물과 같은 강력한 환원제를 처리하기 전 KI, NaCl처럼 알카리 금속 혹은 알카리 토금속의 염을 처리하여 그래핀 산화물에서 미리 H2O를 빼내어 탄소간 이중결합을 부분적으로 복원시키는 공정을 사용할 수 있다. 구체적인 실험예로서 5% 그래핀 산화물 슬러리에 KI 6g를 첨가하고 6일 동안 방치하여 반응을 완결시킨다. 그 후 증류수로 씻어내고 필터링 한다. 기타 그래핀 산화물수용액에 환원제를 투입하는 방법으로서 상기 하이드라진법, KI법 이외에도 NaBH4, Pyrogallol, HI, KOH, Lawesson's reagnet, Vitamin C, Ascorbic acid 등이 있다. 이렇게 제조된 그래핀을 반사법 및 투과법 회절에 의한 (002) 결정면을 분석한 결과 층수가 각각 4.8 및 4.7 ((002)결정면의 FWHM)로 나왔는데 이는 에러범위내에서 비교적 정확한 수치이다. 엑스선 투과율인 경우 본 실험에서는 투과형 시편에서만 가능하였다. 이와같이 투과형 및 반사형 엑스선을 이용하여 다양한 극한 박막의 분석이 가능하려면 엑스선 조사장치, 검출기, 시편이 3차원 공간 (Sphere)에서 x, y, z축으로 움직임이 모두 가능해야 한다. 이를 통하여 기타 숨어있는 결정면의 분석이 가능하고, 저각투과법 및 저각 흡수법의 분석이 가능하며 이에 대한 저각 반산법 (산란법)들의 상호 비교가 가능하다 (표면 거칠기, 엑스선 흡선, 형광 분석등에 반드시 필요).In detail, the chemical reduction method is to disperse well by adding 100 ml of distilled water to 2 g of 3% graphene oxide slurry, and then adding 1 ml of hydrazine hydrate and reducing the process at 100 ° C. for 3 to 24 hours. Filter by filter paper and wash with water and methanol. Before treating a strong reducing agent such as hydrazine hydrate, a salt of an alkali metal or an alkaline earth metal such as KI or NaCl may be used to remove H 2 O from graphene oxide in advance to partially restore carbon-to-carbon double bonds. . As a specific experimental example, 6 g of KI was added to a 5% graphene oxide slurry and left for 6 days to complete the reaction. Then rinse with distilled water and filter. In addition to the hydrazine method, the KI method, there are NaBH 4 , Pyrogallol, HI, KOH, Lawesson's reagnet, Vitamin C, Ascorbic acid, and the like. As a result of analyzing the (002) crystal plane by the reflection method and the diffraction diffraction, the graphene thus produced showed 4.8 and 4.7 (FWHM of the (002) crystal plane), respectively, which are relatively accurate within the error range. In the case of X-ray transmittance, it was possible only in the transmissive specimen. In order to analyze various extreme thin films using transmission and reflection X-rays, the X-ray irradiation apparatus, the detector, and the specimen should all be able to move in the x-, y-, and z-axes in three-dimensional space (Sphere). This enables analysis of other hidden crystal planes, analysis of low angle transmission and low angle absorption, and mutual comparison of low angle half scattering methods (surface roughness, X-ray absorption, fluorescence analysis, etc.). need).
비록 본 발명에서는 엑스선 투과, 엑스선 흡수, 반사에 의한 엑스선 회절, 투과에 의한 엑스선 회절, 특정 엑스선 결정면의 회절, 특정결정면의 록킨커브에 한정하여 실시예를 제시하였지만, 본 발명의 원리는 극 미세 두께를 갖는 그래핀의 엑스선 분석방법 즉 엑스선 회절법, 엑스선 반사법, 엑스선 투과법, 엑스선 흡수법, 엑스선 산란법, 엑스선 형광법, 엑스선 이미지법 등에 직접적으로 적용이 된다.Although the present invention is limited to X-ray transmission, X-ray absorption, X-ray diffraction by reflection, X-ray diffraction by transmission, diffraction of a specific X-ray crystal plane, Rockin curve of the specific crystal surface, the present invention is limited to the extremely fine thickness It is directly applied to X-ray analysis method of graphene having X-ray diffraction method, X-ray reflection method, X-ray transmission method, X-ray absorption method, X-ray scattering method, X-ray fluorescence method, X-ray imaging method.
본 발명은 상기에서 언급한 바와 같이 바람직한 실시예와 관련하여 설명되었으나, 본 발명의 요지를 벗어남이 없는 범위 내에서 다양한 수정 및 변형이 가능하며, 다양한 분야에서 사용 가능하다. 따라서 본 발명의 청구범위는 이건 발명의 진정한 범위 내에 속하는 수정 및 변형을 포함한다.Although the present invention has been described in connection with the preferred embodiment as mentioned above, various modifications and variations are possible without departing from the gist of the present invention, and can be used in various fields. Therefore, the claims of the present invention include modifications and variations that fall within the true scope of the invention.

Claims (30)

  1. (a) 층 수 별로 정의된 기준 그래핀을 준비하는 단계;(A) preparing a reference graphene defined by the number of layers;
    (b) 상기 기준 그래핀에 대하여 XRD 측정을 수행하여 특정 밀러지수를 갖는 그래핀 결정면의 회절 피크를 얻어내는 단계; 및(b) performing XRD measurements on the reference graphene to obtain diffraction peaks of the graphene crystal plane having a specific Miller index; And
    (c) 상기 밀러지수를 갖는 그래핀 결정면의 회절 피크들로부터 FWHM(full width at half maximum) 및 층간간격을 포함한 그래핀 두께에 대한 유효정보를 도출하는 단계; 를 포함하는 그래핀 레퍼런스 도출 방법.(c) deriving valid information on graphene thickness including full width at half maximum (FWHM) and interlayer spacing from diffraction peaks of the graphene crystal surface having Miller index; Graphene reference derivation method comprising a.
  2. 제1항에서,In claim 1,
    상기 (a)단계는 단층 그래핀을 적층하여 층 수 별로 정의된 기준 그래핀을 수득하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법Step (a) is a graphene reference derivation method, characterized in that to obtain a reference graphene defined by the number of layers by stacking single layer graphene
  3. 제1항에서,In claim 1,
    상기 (b)단계는 상기 기준 그래핀에 대한 XRD 측정시, X선 조사각 설정 전에 특정 밀러지수를 갖는 결정면의 록킹커브(rocking curve)를 우선 측정하여 배향성을 확인하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (b) is a graphene reference, characterized in that to determine the orientation by first measuring the rocking curve (rocking curve) of the crystal surface having a specific Miller index before setting the X-ray irradiation angle for the reference graphene XRD Derivation method.
  4. 제3항에서,In claim 3,
    상기 (b)단계는 상기 기준 그래핀에 대한 XRD 측정시, X선 조사각을 하기 [조사각 도출식]에 따라 도출된 각도범위 내에서 설정하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.The step (b) is a graphene reference derivation method, characterized in that for setting the X-ray irradiation angle in the XRD measurement for the reference graphene within the angular range derived according to the [irradiation angle derivation formula].
    X선 조사각 = (2θ(hkl)÷2)±1˚X-ray irradiation angle = (2θ (hkl) ÷ 2) ± 1˚
    2θ(hkl) : 특정 밀러지수를 갖는 기준 그래핀 결정면의 피크 센터의 회절각2θ (hkl): diffraction angle of peak center of reference graphene crystal plane with specific Miller index
  5. 제1항에서,In claim 1,
    상기 (b)단계는 상기 기준 그래핀에 대한 XRD 측정시 GI SAXS 측정방법을 수행하여, 밀러지수가 (002)인 결정면을 제외한 나머지 결정면의 회절 피크를 얻는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (b) is a graphene reference derivation method, characterized in that to perform a GI SAXS measurement method for XRD measurement for the reference graphene, to obtain the diffraction peak of the remaining crystal plane except the crystal plane of Miller index (002).
  6. 제5항에서,In claim 5,
    상기 (b)단계는 평행빔 X선 광학기(Parallel beam X-ray optics)를 이용하여 상기 기준 그래핀에 대한 XRD 측정을 수행하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (b) is a graphene reference derivation method, characterized in that for performing the XRD measurement for the reference graphene using parallel beam X-ray optics (Parallel beam X-ray optics).
  7. 제6항에서,In claim 6,
    상기 (b)단계의 XRD 측정은 2theta(쎄타)-ω(오메가) 모드에 의한 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.The XRD measurement of step (b) is a graphene reference derivation method, characterized in that by the 2 theta (theta) -ω (omega) mode.
  8. 제1항에서,In claim 1,
    상기 (b)단계는 상기 기준 그래핀에 대한 XRD 측정시 밀러지수가 (002)인 결정면의 회절 피크를 얻어내는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (b) is a graphene reference derivation method, characterized in that to obtain a diffraction peak of the crystal plane with a Miller index (002) in the XRD measurement for the reference graphene.
  9. 제8항에서,In claim 8,
    상기 (b)단계는 평행빔 X선 광학기(Parallel beam X-ray optics)를 이용하여 상기 기준 그래핀에 대한 XRD 측정을 수행하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (b) is a graphene reference derivation method, characterized in that for performing the XRD measurement for the reference graphene using parallel beam X-ray optics (Parallel beam X-ray optics).
  10. 제9항에서,In claim 9,
    상기 (b)단계의 XRD 측정은 2theta(쎄타)-ω(오메가) 모드에 의한 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.The XRD measurement of step (b) is a graphene reference derivation method, characterized in that by the 2 theta (theta) -ω (omega) mode.
  11. 제8항에서,In claim 8,
    상기 (c)단계는 가우시안 함수(Gaussian Function) 또는 로렌찌안 함수(Lorentian Function)를 이용하여 상기 기준 그래핀의 층 수 별 피크에 대한 피크피팅을 수행하여 상기 유효정보를 도출하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.In the step (c), the peak information for each layer peak of the reference graphene is derived using a Gaussian function or a Lorentian function to derive the valid information. How to get a pin reference.
  12. 제8항에서,In claim 8,
    상기 (c)단계는 하기 [층간간격 도출식]에 의해 기준 그래핀의 층간간격(d002)을 도출하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (c) is a graphene reference derivation method, characterized in that to derive the interlayer spacing (d 002 ) of the reference graphene by the [interlayer spacing derivation formula].
    [층간간격 도출식][Interval of Floor Interval]
    d(002) = nλ/2sinθ(002) d (002) = nλ / 2sinθ (002)
    d002 : 결정면의 밀러지수가 (002)인 기준 그래핀의 층간간격d 002 : Interlayer spacing of reference graphene with Miller index of crystal plane (002)
    λ : X-ray 파장λ: X-ray wavelength
    2θ(002) : 밀러지수가 (002)인 기준 그래핀 결정면의 피크 센터의 회절각2θ (002) : diffraction angle of the peak center of the reference graphene crystal plane with Miller index (002)
    n : 정수로 표현되는 회절피크의 차수n: degree of diffraction peak expressed as an integer
  13. 제8항에서,In claim 8,
    상기 (b)단계는 XRD 측정시, X선 조사각 설정 전에 밀러지수 (002)를 갖는 그래핀 결정면의 록킹커브(rocking curve)를 우선 측정하여 배향성을 확인하고, 상기 X선 조사각을 하기 [조사각 도출식]에 따라 도출된 각도범위 내에서 설정하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법.Step (b) is to determine the orientation by measuring the rocking curve of the graphene crystal surface having a Miller index (002) prior to setting the X-ray irradiation angle in XRD measurement, and the X-ray irradiation angle [ Survey angle derivation formula] according to the graphene reference derivation method characterized in that it is set within the derived range.
    [조사각 도출식][Derivation angle of expression]
    X선 조사각 = (2θ(002)÷2)±1˚X-ray irradiation angle = (2θ (002) ÷ 2) ± 1˚
    2θ(002) : 밀러지수가 (002)인 기준 그래핀 결정면의 피크 센터의 회절각2θ (002) : diffraction angle of the peak center of the reference graphene crystal plane with Miller index (002)
  14. 제1항 내지 제13항 중 어느 한 항에서,The method according to any one of claims 1 to 13,
    (d) 상기 유효정보에 기초하여 검량선을 작성하는 단계; 를 더 포함하는 것을 특징으로 하는 그래핀 레퍼런스 도출 방법(d) creating a calibration curve based on the valid information; Graphene reference derivation method characterized in that it further comprises
  15. (A) 분석대상 나노박막에 대하여 XRD 측정을 수행하는 단계; 및(A) performing an XRD measurement on the analyte nano thin film; And
    (B) 상기 XRD 측정 결과를 제14항의 그래핀 레퍼런스 도출 방법에 따라 작성된 검량선과 대비하여 상기 분석대상 나노박막의 두께를 포함하는 데이터를 측정하는 단계; 를 더 포함하는 것을 특징으로 하는 나노박막 분석 방법.(B) measuring the data including the thickness of the analyte nano thin film by comparing the XRD measurement results with the calibration curve prepared according to the graphene reference derivation method of claim 14; Nano thin film analysis method characterized in that it further comprises.
  16. 제15항에서,The method of claim 15,
    상기 (A)단계의 분석대상 나노박막은 그래핀막이고,The nano thin film to be analyzed in step (A) is a graphene film,
    상기 (B)단계의 데이터는 분석대상 그래핀막의 그래핀 층 수 및 두께를 포함하는 것을 특징으로 하는 나노박막 분석 방법.The data of step (B) is a nano thin film analysis method comprising the graphene layer number and thickness of the graphene film to be analyzed.
  17. 제16항에서,The method of claim 16,
    상기 (B)단계의 검량선은 상기 기준 그래핀의 층 수 별 FWHM이 하기 [도출범위]에 부합하는 조건에서 작성된 것으로서, 상기 분석대상 그래핀막의 그래핀 층 수를 측정할 때, 밀러지수가 (002)인 그래핀 결정면의 회절 피크가 관찰되는 경우 상기 검량선과 대비하여 그래핀 층 수를 도출하는 것을 특징으로 하는 나노박막 분석 방법.The calibration curve of step (B) is made under the condition that the FWHM for each layer of the reference graphene meets the following [Derivation range], and when measuring the graphene layer number of the graphene film to be analyzed, the Miller index ( 002) when the diffraction peak of the graphene crystal surface is observed, the nano thin film analysis method, characterized in that the number of graphene layer is derived from the calibration curve.
    [도출범위][Derivation range]
    ① 그래핀 3층 : 4.663~5.069˚±1.5˚① Graphene 3 layer: 4.663 ~ 5.069˚ ± 1.5˚
    ② 그래핀 4층 : 3.207~3.310˚±1.0˚② Graphene 4 layer: 3.207 ~ 3.310˚ ± 1.0˚
    ③ 그래핀 5층 : 1.798~1.8440˚±0.5˚③ Graphene 5F: 1.798 ~ 1.8440˚ ± 0.5˚
    ④ 그래핀 6층 : 1.510~1.5510˚±0.4˚④ 6 layers of graphene: 1.510 ~ 1.5510˚ ± 0.4˚
    ⑤ 그래핀 7층 : 1.255~1.296˚±0.4˚⑤ Graphene 7F: 1.255 ~ 1.296˚ ± 0.4˚
  18. 제16항에서,The method of claim 16,
    상기 (B)단계는 하기 [그래핀 두께 산출식 1]에 의해 분석대상 그래핀막의 두께를 측정하는 것을 특징으로 하는 나노박막 분석 방법.Step (B) is a nano thin film analysis method, characterized in that for measuring the thickness of the graphene film to be analyzed by the following [graphene thickness calculation formula 1].
    [그래핀 두께 산출식 1][Calculation of Graphene Thickness 1]
    원자 중심간 거리를 기준으로 한 분석대상 그래핀막의 두께(D1) = d002 ×(NL-1)Thickness of the graphene film to be analyzed based on the distance between atomic centers (D 1 ) = d 002 × (N L -1)
    d002 : 결정면의 밀러지수가 (002)인 다층 기준 그래핀의 층간간격d 002 : Interlayer spacing of multilayer reference graphene having Miller index of crystal plane (002)
    NL : 분석대상 그래핀막의 그래핀 층 수N L : Number of graphene layers in the graphene film to be analyzed
  19. 제16항에서,The method of claim 16,
    상기 (B)단계는 하기 [그래핀 두께 산출식 2]에 의해 분석대상 그래핀막의 두께를 측정하는 것을 특징으로 하는 나노박막 분석 방법.Step (B) is a nano thin film analysis method, characterized in that for measuring the thickness of the graphene film to be analyzed by the [graphene thickness calculation formula 2].
    [그래핀 두께 산출식 2]Graphene Thickness Calculation Equation 2
    원자의 최대 외경간 거리를 기준으로 한 분석대상 그래핀막의 두께(D2) = d002 × NL The thickness of the graphene film to be analyzed (D 2 ) based on the maximum outer diameter distance of atoms (d 2 ) = d 002 × N L
    d002 : 결정면의 밀러지수가 (002)인 다층 그래핀의 층간간격d 002 : Interlayer spacing of multilayer graphene with Miller index of crystal plane (002)
    NL : 분석대상 그래핀막의 그래핀 층 수N L : Number of graphene layers in the graphene film to be analyzed
  20. 제16항에서,The method of claim 16,
    상기 (B)단계의 검량선은 기준 그래핀의 층 수 별 FWHM을 y축으로 하고, 상기 기준 그래핀의 두께(D)로부터 구한 그래핀 두께의 역수(1/D)를 x축으로 하여 얻어낸 직선의 기울기 14~40, y절편 -2~2 조건이 충족되는 것을 특징으로 하는 나노박막 분석 방법.The calibration curve of step (B) is a straight line obtained by using the FWHM for each layer of the reference graphene as the y-axis and the inverse (1 / D) of the graphene thickness obtained from the thickness (D) of the reference graphene as the x-axis. The slope of 14 to 40, y-intercept-2 to 2 conditions, characterized in that the nano-film analysis method.
  21. 온도조건 278~328°K 및 습도조건 70% 미만으로 제어되며 시편이 안치되는 챔버;A chamber in which the specimen is placed and controlled at a temperature of 278 to 328 ° K and a humidity of less than 70%;
    상기 챔버 내 시편에 X선을 조사하는 평행빔 X선 조사장치; 및A parallel beam X-ray irradiation apparatus for irradiating X-rays to the specimen in the chamber; And
    상기 챔버 내 시편을 투과하거나 상기 시편에 부딛혀 반사 또는 회절하는 X선을 검출하는 검출장치; 를 포함하여 구성되는 X선 분석 장치.A detection device that detects X-rays that transmit or reflect or diffract the specimen in the chamber; X-ray analysis device configured to include.
  22. 제21항에서,The method of claim 21,
    상기 챔버 내에는 시편을 3축(x-y-z축)으로 축회전시킬 수 있는 시편고정대가 구비된 것을 특징으로 하는 X선 분석 장치.The chamber is provided with an X-ray analyzer, characterized in that the specimen holder for rotating the specimen in three axes (x-y-z axis).
  23. 제21항에서,The method of claim 21,
    상기 평행빔 X선 조사장치는 종방향과 횡방향으로 원심회전하도록 구성된 것을 특징으로 하는 X선 분석 장치.The parallel beam X-ray irradiation apparatus is X-ray analysis apparatus, characterized in that configured to centrifugal rotation in the longitudinal direction and the transverse direction.
  24. 제21항에서,The method of claim 21,
    상기 검출장치는 종방향과 횡방향으로 원심회전하도록 구성된 것을 특징으로 하는 X선 분석 장치.The detection device is X-ray analysis device, characterized in that configured to centrifugal rotation in the longitudinal and transverse direction.
  25. 제21항에서,The method of claim 21,
    상기 챔버 내 시편에 열을 가하는 열처리장치가 구비된 것을 특징으로 하는 X선 분석 장치.X-ray analyzer, characterized in that provided with a heat treatment device for applying heat to the specimen in the chamber.
  26. 제21항에서,The method of claim 21,
    상기 챔버 내 시편에 수분을 가하는 가습장치가 구비된 것을 특징으로 하는 X선 분석 장치.X-ray analyzer, characterized in that the humidifier is provided for applying moisture to the specimen in the chamber.
  27. (a) 제21항 내지 제26항 중 어느 한 항의 X선 분석 장치를 준비하는 단계;(A) preparing an X-ray analysis device of any one of claims 21 to 26;
    (b) 상기 챔버에 층수 1~10층, 크기 0.3×0.3㎝ 이상인 그래핀 시편을 안치시키는 단계; 및(b) placing the graphene specimen having a layer number of 1 to 10 layers and a size of 0.3 × 0.3 cm or more in the chamber; And
    (c) 상기 평행빔 X선 조사장치로 상기 그래핀 시편에 X선을 조사하여 투과하거나 회절 또는 반사된 X선을 상기 검출장치로 검출하여 분석하는 단계; 를 포함하는 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법.(c) detecting and analyzing X-rays transmitted or diffracted or reflected by the detection apparatus by irradiating X-rays on the graphene specimen with the parallel beam X-ray irradiation apparatus; X-ray analysis method for the graphene having an extremely fine thickness comprising a.
  28. 제27항에서,The method of claim 27,
    상기 (c)단계의 X선 조사각 및 검출장치의 배치는 2θ(쎄타)-ω(오메가) 방법으로 설정하는 것을 특징으로 하는 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법.X-ray irradiation angle and the arrangement of the detection device of the step (c) is X-ray analysis method for the graphene having an extremely fine thickness, characterized in that the 2θ (theta) -ω (omega) method is set.
  29. 제28항에서,The method of claim 28,
    상기 (c)단계는 시편에 조사되는 X선의 각도를 하기 [조사각 도출식]에 따라 도출된 범위 내에서 설정하는 것을 특징으로 하는 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법.The step (c) is an X-ray analysis method for graphene having an extremely fine thickness, characterized in that the angle of the X-ray irradiated to the specimen is set within the range derived according to the [irradiation angle derivation formula].
    [조사각 도출식][Derivation angle of expression]
    X선 조사각 = (2θ(hkl)÷2)±1˚X-ray irradiation angle = (2θ (hkl) ÷ 2) ± 1˚
    2θ(hkl) : 특정 밀러지수를 갖는 기준 그래핀 결정면의 피크 센터의 회절각2θ (hkl): diffraction angle of peak center of reference graphene crystal plane with specific Miller index
  30. 제28항에서,The method of claim 28,
    상기 (c)단계에서 상기 검출장치는 시편을 기준으로 하기 [검출각 도출식]에 따라 도출된 각도범위 내에서 설치하는 것을 특징으로 하는 극 미세 두께를 갖는 그래핀에 대한 X선 분석방법.In the step (c), the detection device is X-ray analysis method for the graphene having an extremely fine thickness, characterized in that installed in the angular range derived according to the [detection angle derivation formula] based on the specimen.
    [검출각 도출식][Detecting angle derived expression]
    X선 검출각 = (2θ(hkl)÷2)±1˚X-ray detection angle = (2θ (hkl) ÷ 2) ± 1˚
    2θ(hkl) : 특정 밀러지수를 갖는 기준 그래핀 결정면의 피크 센터의 회절각2θ (hkl): diffraction angle of peak center of reference graphene crystal plane with specific Miller index
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