WO2012039533A1 - Graphene structure, method of forming the graphene structure, and transparent electrode including the graphene structure - Google Patents

Graphene structure, method of forming the graphene structure, and transparent electrode including the graphene structure Download PDF

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WO2012039533A1
WO2012039533A1 PCT/KR2011/001642 KR2011001642W WO2012039533A1 WO 2012039533 A1 WO2012039533 A1 WO 2012039533A1 KR 2011001642 W KR2011001642 W KR 2011001642W WO 2012039533 A1 WO2012039533 A1 WO 2012039533A1
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layer
graphene
graphitizing catalyst
amorphous carbon
forming
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PCT/KR2011/001642
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French (fr)
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Ki Bum Kim
Hong Hie Lee
Hyun Mi Kim
Seong Yong Cho
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Snu R&Db Foundation
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/182—Graphene
    • C01B32/184—Preparation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/0605—Carbon
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B1/00—Single-crystal growth directly from the solid state
    • C30B1/02—Single-crystal growth directly from the solid state by thermal treatment, e.g. strain annealing
    • C30B1/023—Single-crystal growth directly from the solid state by thermal treatment, e.g. strain annealing from solids with amorphous structure
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
    • H01L21/02491—Conductive materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02494—Structure
    • H01L21/02513—Microstructure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02524—Group 14 semiconducting materials
    • H01L21/02527—Carbon, e.g. diamond-like carbon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02656—Special treatments
    • H01L21/02664—Aftertreatments
    • H01L21/02667—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1884—Manufacture of transparent electrodes, e.g. TCO, ITO
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a method of forming graphene using an amorphous carbon layer, a graphene structure manufactured by using the method, and a transparent electrode including the graphene structure, and more particularly, to a method of forming graphene by metallic contact of an amorphous carbon layer, a graphene structure manufactured by using the method, and a transparent electrode including graphene manufactured by using the method.
  • Graphene refers to a two-dimensional and honeycomb-structural thin film that is composed of one one-carbon (C) atom sheet or a plurality of one-carbon (C) atom sheets.
  • C one-carbon
  • C carbon
  • sp 2 hybrid orbitals When carbon atoms are chemically bonded via sp 2 hybrid orbitals, a two-dimensional carbon hexagonal plane is formed. Carbon has four outermost electrons, and during bonding, the four electrons are hybridized to take part in the bonding.
  • Examples of a carbon bond are an sp 3 bond and an sp 2 bond.
  • a square diamond is formed, and when carbon atoms are bonded by only sp 2 bonds, graphite or graphene, that is, one layer of graphite, is formed.
  • electrons that are supposed to be present only in s orbitals or p orbitals are present in sp 2 and sp 3 hybrid orbitals, which are combinations of s orbitals and p orbitals.
  • the sp 2 hybrid orbital Since in an sp 2 hybrid orbital, one electron is present in an s orbital and two electrons are present in a p orbital, the sp 2 hybrid orbital includes a total of three electrons and an energy potential of each electron is the same. A hybrid orbital is more stable than an s orbital and a p orbital.
  • Graphene is a collection of carbon atoms each having a planar structure formed by sp 2 bonds, and a thickness of one graphene sheet is equivalent to the size of one carbon atom, for example, about 0.3 nm.
  • Graphene has a metallic property, conductivity in a layer direction, and excellent thermal conductivity.
  • charge carriers have high mobility, thereby enabling manufacturing of high-speed electronic devices.
  • a graphene sheet has an electron mobility of about 20,000 to 50,000 cm 2 /Vs.
  • Graphene has high dynamic rigidity and chemical stability, and semi-conductive and conductive properties, and a small thickness.
  • graphene may be easily used in manufacturing flat panel display devices, transistors, energy storage devices, and nano-sized electronic devices. Also, graphene may be easily used in manufacturing devices by using conventional semiconductor process techniques, and in particular, enables production of large-size highly integrated devices.
  • ITO indium thin oxide
  • ITO indium thin oxide
  • the price of indium (In) is increasing and chances of indium depletion are also increasing, thereby increasing manufacturing costs.
  • ITO does not have flexibility and thus is not suitable for use in flexible devices.
  • the present invention provides a graphene structure having high transmittance and electrical conductivity and a transparent electrode using the graphene structure.
  • the present invention also provides a method of forming graphene in which graphene is formed directly on a substrate for fabricating a device, and a transparent electrode formed by using the method.
  • a method of forming graphene including: forming an amorphous carbon layer on a substrate; forming a graphitizing catalyst layer on the amorphous carbon layer; and heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming a graphene layer on the graphitizing catalyst layer.
  • the heat treatment, the graphitizing catalyst layer agglomerates.
  • a stack structure including the graphitizing catalyst layer and the graphene layer has transmittance of 80% or higher.
  • a stack structure including the graphitizing catalyst layer and the graphene layer has a sheet resistance of 10 ⁇ / ⁇ to 50 ⁇ / ⁇ .
  • the graphitizing catalyst layer includes a material for crystallizing amorphous carbon.
  • the graphitizing catalyst layer includes at least one metal or metal alloy selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), and rhodium (Rh).
  • the method may further include forming a graphitizing catalyst layer on the substrate and heat treating the graphitizing catalyst layer, before the forming of the amorphous carbon layer.
  • the method may further include removing the substrate after the heat treatment.
  • the method may further include removing the graphitizing catalyst layer after the heat treatment.
  • a method of forming graphene including: forming a graphitizing catalyst layer on a substrate; forming an amorphous carbon layer on the graphitizing catalyst layer; and heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming an graphene layer on at least one of upper and lower surfaces of the graphitizing catalyst layer.
  • a graphene structure including: graphitizing catalyst particles; and a graphene layer on the graphitizing catalyst particles.
  • a transparent electrode including: graphitizing catalyst particles; and a graphene layer on the graphitizing catalyst particles.
  • FIG. 1 is a sectional view of a graphene structure according to an embodiment of the present invention
  • FIGS. 2 to 7 are sectional views for explaining a method of forming graphene according to an embodiment of the present invention.
  • FIG. 8 shows a transmission electron microscope (TEM) image of a graphene structure according to an embodiment of the present invention
  • FIG. 9 shows Raman spectra of a graphene structure according to an embodiment of the present invention.
  • FIG. 10 is a graph showing sheet resistance measurement results of a graphene structure according to an embodiment of the present invention.
  • FIG. 11 is a graph showing transmittance measurement results of a graphene structure according to an embodiment of the present invention.
  • FIGS. 12 to 15 are sectional views for explaining a method of forming graphene according to another embodiment of the present invention.
  • FIG. 16 is a sectional view of an example of a solar cell using a graphene structure according to an embodiment of the present invention.
  • FIG. 17 is a sectional view of another example of a solar cell using a graphene structure according to an embodiment of the present invention.
  • FIG. 1 is a sectional view of a graphene structure according to an embodiment of the present invention.
  • graphitizing catalyst particles 120P and a graphene layer 130 may be formed on a substrate 100.
  • the graphitizing catalyst particles 120P may be agglomerates formed by heat treating a thin-film type graphitizing catalyst layer.
  • the substrate 100 may be formed of a material that does not dissolve carbon and that does not cause carbon to diffuse.
  • the substrate 100 may be a glass substrate, a quartz substrate, or a sapphire substrate.
  • the substrate 100 may be a substrate including oxides.
  • the graphitizing catalyst particles 120P may be a material that is capable of crystallizing an amorphous carbon layer. Also, the graphitizing catalyst particles 120P may be a metallic material. For example, the graphitizing catalyst particles 120P may include at least one material selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), and rhodium (Rh).
  • the graphene layer 130 may include one graphene sheet or a plurality of graphene sheets.
  • the graphene layer 130 may be formed on the graphitizing catalyst particles 120P, and may be a continuous film.
  • the graphene layer 130 may have an uneven lower portion formed due to the graphitizing catalyst particles 120P and an even upper portion.
  • the graphene layer 130 may also have an uneven upper portion formed due to the graphitizing catalyst particles 120P.
  • the stack structure of the graphitizing catalyst particles 120P and the graphene layer 130 is referred to as a graphene structure herein.
  • the graphene structure may be used as a transparent electrode.
  • the transparent electrode may be used in image sensors, solar cells, and light emitting devices, which require light transmittance and electrical conductivity.
  • the transparent electrode may also be used as an electrode layer in various displays, such as a plasma display panel (PDP), a liquid crystal display (LCD), or a flexible display.
  • FIGS. 2 to 7 are sectional views for explaining a method of forming graphene according to an embodiment of the present invention.
  • an amorphous carbon layer 110 may be formed on the substrate 100.
  • the amorphous carbon layer 110 may be formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD), such as sputtering, molecular beam epitaxy (MBE), or thermal evaporation.
  • PVD physical vapor deposition
  • CVD chemical vapor deposition
  • MBE molecular beam epitaxy
  • the amorphous carbon layer 110 may be formed to have a thickness of a few nanometers or tens of nanometers, for example, a thickness of 2 nm to 30 nm.
  • a graphitizing catalyst layer 120 may be formed on the amorphous carbon layer 110.
  • the graphitizing catalyst layer 120 may include a metallic material that dissolves carbon. That is, the metallic material of the graphitizing catalyst layer 120 may be a material that dissolves carbon to form a carbon solution and crystallizes the amorphous carbon layer 110.
  • the graphitizing catalyst layer 120 may include at least one material selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), and rhodium (Rh).
  • the graphitizing catalyst layer 120 may be formed by PVD, CVD, atomic layer deposition (ALD), or electroplating. In addition, the formation of the graphitizing catalyst layer 120 and the formation of the amorphous carbon layer 110, which has been described with reference to FIG. 2, may be performed in-situ.
  • the graphitizing catalyst layer 120 may be formed to have a thickness of a few nanometers to tens of nanometers, for example, 10 nm to 30 nm.
  • the stack structure including the amorphous carbon layer 110 and the graphitizing catalyst layer 120 on the substrate 100 may be heat treated.
  • the heat treatment may be performed at a temperature of 300°C to 1200°C. When the heat treatment is performed at lower temperatures, carbon may not be dissolved and diffused, and when the heat treatment is performed at higher temperatures, the substrate 100 may be damaged.
  • the heat treatment may be performed under an inert gas, for example, argon (Ar) gas atmosphere.
  • hydrogen (H 2 ) gas may be added thereto.
  • argon gas and hydrogen gas are used in combination, a volumetric ratio of the argon gas to the hydrogen gas may be 2:1.
  • the heat treatment process may be performed for, for example, 5 minutes to 10 minutes.
  • the heat treatment process may be performed using a rapid thermal annealing (RTA) device or a typical furnace. After the heat treatment process is performed, the stack structure including the amorphous carbon layer 110 and the graphitizing catalyst layer 120 on the substrate 100 may be cooled.
  • the cooling process may be a natural cooling.
  • the graphene layer 130 may be formed when the amorphous carbon layer 110 is dissolved by and diffused into the graphitizing catalyst layer 120 during the heat treatment process. That is, during the heat treatment process, the amorphous carbon layer 110 is dissolved by the graphitizing catalyst layer 120 and thus carbon atoms are released. And, through the heat treatment process and the cooling process, the carbon atoms released by the graphitizing catalyst layer 120 are realigned in the graphitizing catalyst layer 120, thereby forming the graphene layer 130.
  • the graphene layer 130 may be formed by crystallizing amorphous carbon atoms, wherein the crystallization may be induced by the graphitizing catalyst layer 120.
  • the graphitizing catalyst particles 120P and the graphene layer 130 may be formed.
  • the graphitizing catalyst particles 120P may be formed as a result of agglomeration of the graphitizing catalyst layer 120 of FIG. 5 in the heat treatment process. Sizes of the graphitizing catalyst particles 120P may differ according to a thickness of the graphitizing catalyst layer 120 and a heat treatment temperature.
  • the graphene layer 130 may be formed by crystallizing all the carbon atoms contained in the amorphous carbon layer 110. Accordingly, a thickness of the graphene layer 130 may be dependent upon a thickness of the amorphous carbon layer 110. If the thickness of the graphene layer 130 is small, as illustrated, the graphene layer 130 may have an uneven surface formed due to the graphitizing catalyst particles 120P. In another embodiment, as illustrated in FIG. 1, the graphene layer 130 may be formed to have an even surface.
  • the substrate 100 may be removed.
  • the substrate 100 may be removed using an etchant.
  • the stack structure including the graphitizing catalyst particles 120P and the graphene 130 remains.
  • the graphene structure may be placed on another substrate.
  • the graphitizing catalyst particles 120P may be removed.
  • the graphitizing catalyst particles 120P may be selectively removed by, for example, wet etching or dry etching. The removal process may be performed after the substrate 100 is removed or before the substrate 100 is removed.
  • the graphitizing catalyst layer 120 may be additionally formed on the substrate 100. That is, the graphitizing catalyst layer 120 may be formed on upper and lower surfaces of the amorphous carbon layer 110.
  • a heat treatment may be performed thereon. That is, after the graphitizing catalyst particles 120P are formed on the substrate 100 by a heat treatment, the amorphous carbon layer 110 is formed. By doing so, a contact area between carbon atoms and a graphitizing catalyst material may be increased.
  • a graphene layer may be formed by using a mechanical separation method in which graphene is separated from a graphite crystal or a silicon carbide (SiC) crystal thermal decomposition method.
  • SiC silicon carbide
  • a scotch tape method as a fine mechanical separation method in which scotch tape is attached to and then separated from a graphite sample, thereby obtaining a graphene sheet separated from the graphite sample on a surface of the scotch tape.
  • SiC silicon carbide
  • a deposition process may be used to form graphene.
  • graphene is epitaxially grown on a sapphire substrate by MBE or CVD.
  • the epitaxial growth may be easily performed due to crystallographic compatibility between graphene and the sapphire substrate.
  • a graphene layer is formed by a heat treatment after an amorphous carbon layer and a graphitizing catalyst layer are deposited according to a method of forming graphene according to an embodiment of the inventive concept, large-size graphene may be formed using a simple process.
  • a graphene layer is formed directly on a substrate, transferring separately formed graphene onto a substrate for fabricating a device is not needed. Accordingly, the manufacturing process is simplified, and graphene damage, which may occur when graphene is transferred, may be prevented.
  • FIG. 8 shows a transmission electron microscope (TEM) image of a graphene structure according to an embodiment of the present invention.
  • FIG. 8 analysis results obtained using a TEM are shown.
  • a graphene structure including an amorphous carbon layer having a thickness of 10 nm and a graphitizing catalyst layer formed of nickel (Ni) having a thickness of 10 nm was heat treated at a temperature of 500°C.
  • Ni nickel
  • the substrate 100 was a quartz substrate, and a dark region in FIG. 8 corresponds to a protection layer formed in a sample preparation process.
  • the graphene layer 130 was formed on the substrate 100, and has a lattice fringe. It is known that a crystallization temperature of amorphous carbon is equal to or higher than 2000°C. However, according to a method of forming graphene according to an embodiment of the present invention, crystallization may be induced by metallic particles such as nickel (Ni) and may be performed at a temperature lower than the known crystallization temperature. In the present embodiment, it was confirmed that graphene was obtained by crystallizing carbon atoms at a temperature of 500°C through a heat treatment process.
  • Ni nickel
  • FIG. 9 shows Raman spectra of a graphene structure according to an embodiment of the present invention.
  • Raman spectra according to heat treatment temperature are shown. Formation of graphene was confirmed in view of presence of the G peak (about 1580 cm -1 ) and the 2D peak (about 2690 cm -1 ).
  • the G peak is a peak showing presence of an sp 2 bond of graphene. As illustrated, it was confirmed that graphene was formed when the heat treatment was performed at a temperature equal to or higher than 400°C.
  • the D peak (about 1340 cm -1 ) is related to a grain size of graphene, and larger grains may have weaker peaks.
  • a thickness of a graphene layer may be identified in view of a ratio of the G peak (about 1580 cm -1 ) and the 2D peak (about 2690 cm -1 ).
  • FIG. 10 is a graph showing sheet resistance measurement results of a graphene structure according to an embodiment of the present invention.
  • a sheet resistance of a graphene structure including graphitizing catalyst particles may be in a range of about 10 ⁇ / ⁇ to about 50 ⁇ / ⁇ .
  • the graphene structure may have a sheet resistance of about 20 ⁇ / ⁇ .
  • amorphous carbon that is not heat treated has a specific resistance of 10,000 ⁇ cm and nickel (Ni) has a specific resistance of 30 ⁇ cm
  • a sheet resistance of the graphene structure seems to be similar to that of nickel (Ni). That is, the sheet resistance of the graphene structure is similar to a sheet resistance of metal. Accordingly, it is confirmed that a graphene layer according to an embodiment of the present invention has high electrical conductivity.
  • FIG. 11 is a graph showing transmittance measurement results of a graphene structure according to an embodiment of the present invention.
  • the transmittance analysis was performed using an ultraviolet (UV)-visible spectrophotometer, and in the analysis results, transmittance is represented by %.
  • UV ultraviolet
  • the transmittance is increased to 80% or more.
  • the transmittance is about 75% or more.
  • an amorphous carbon layer having a thickness of 10 nm has transmittance of about 57%.
  • the nickel layer has transmittance of nearly 100% and higher heat treatment temperatures lead to higher transmissibilities.
  • a graphene structure according to an embodiment of the present invention has higher transmittance than an amorphous carbon layer.
  • nickel (Ni) particles as graphitizing catalyst particles does not affect transmittance of the graphene structure.
  • FIGS. 12 to 15 are sectional views for explaining a method of forming graphene according to another embodiment of the present invention. In the present embodiment, a description presented with reference to FIGS. 2 to 6 will not be provided herein.
  • a graphitizing catalyst layer 220 may be formed on a substrate 200.
  • the graphitizing catalyst layer 220 may include a metallic material that dissolves carbon.
  • the graphitizing catalyst layer 220 may be formed by PVD, CVD, ALD, or electroplating.
  • a thickness of the graphitizing catalyst layer 220 may be in a range of a few nanometers to tens of nanometers, for example, 2 nm to 30 nm.
  • an amorphous carbon layer 210 may be formed on the graphitizing catalyst layer 220.
  • the amorphous carbon layer 210 may be formed by PVD, such as sputtering or thermal evaporation.
  • the amorphous carbon layer 210 may be formed to have a thickness of a few nanometers to tens of nanometers, for example, 10 nm to 30 nm.
  • the stack structure including the graphitizing catalyst layer 220 and the amorphous carbon layer 210 on the substrate 200 may be heat treated.
  • the heat treatment process may be performed at a temperature of 300°C to 1200°C.
  • the heat treatment may be performed under an inert gas, for example, argon (Ar) gas atmosphere.
  • hydrogen (H 2 ) gas may be added thereto.
  • argon gas and hydrogen gas are used in combination, a volumetric ratio of the argon gas to the hydrogen gas may be 2:1.
  • the heat treatment process may be performed for, for example, 5 minutes to 10 minutes.
  • the heat treatment process may be performed using a rapid thermal annealing (RTA) device or a typical furnace.
  • RTA rapid thermal annealing
  • the stack structure including the amorphous carbon layer 210 and the graphitizing catalyst layer 220 on the substrate 200 may be cooled.
  • the cooling process may be a natural cooling.
  • graphitizing catalyst particles 220P and a graphene layer 230 may be formed.
  • the graphitizing catalyst particles 220P may be formed as a result of agglomeration of the graphitizing catalyst layer 220 of FIG. 14 in the heat treatment process.
  • the graphene layer 230 may be formed when the amorphous carbon layer 210 is dissolved by and diffused into the graphitizing catalyst layer 220 during the heat treatment process.
  • the graphene layer 230 may be formed by the graphitizing catalyst layer 220 inducing crystallization of amorphous carbon.
  • the graphene layer 230 may be formed on upper and lower surfaces of the graphitizing catalyst layer 220. In another embodiment, the graphene layer 230 may be formed only one of the upper and lower surfaces of the graphitizing catalyst layer 220.
  • FIG. 16 is a sectional view of an example of a solar cell using a graphene structure according to an embodiment of the present invention.
  • a solar cell is a device in which solar light energy is converted into electric energy by using a semiconductor property.
  • a solar cell includes basically a diode having a pn junction, and an operational principle thereof will now be described in detail.
  • solar light having energy greater than an energy band gap of a semiconductor is incident on a pn junction of a solar cell, electron-hole pairs are generated, and from among the electron-hole pairs, electrons migrate to an n layer and holes migrate to a p layer due to an electric field formed at the pn junction, thereby generating photovoltaic power between the p and n layers. If a load or system is connected to ends of a solar cell when photovoltaic power is generated, a current flows, thereby generating electric power.
  • the solar cell according to the present embodiment includes a substrate 400, and graphitizing catalyst particles 420P, a graphene layer 430, a semiconductor layer 440, and an upper electrode layer 450 sequentially disposed in this order on the substrate 400.
  • the substrate 400 may be a glass, quartz, or transparent plastic substrate.
  • graphene structure used herein refers to a stack structure including the graphitizing catalyst particles 420P and the graphene layer 430, and the upper electrode layer 450 may be a transparent electrode.
  • the graphene structure may be manufactured by using the method described with reference to FIGS. 2 to 6.
  • the substrate 400 may also be a substrate that is used for forming the graphene structure.
  • the semiconductor layer 440 may be formed on the graphene layer 430, and may have a pin structure including a p-type semiconductor layer 442, an i-type semiconductor layer 444, and an n-type semiconductor layer 446 sequentially stacked in this order.
  • Each of the p-type semiconductor layer 442, the intrinsic(i)-type semiconductor layer 444, and the n-type semiconductor layer 446 may be single crystal silicon, polycrystal silicon, amorphous silicon, or a compound semiconductor.
  • the i-type semiconductor layer 444 is depleted by the p-type semiconductor layer 442 and the n-type semiconductor layer 446 and an electric field occurs in the i-type semiconductor layer 444. Holes and electrons generated by solar light are drifted due to the electric field and gather in the p-type semiconductor layer 442 and the n-type semiconductor layer 446, respectively.
  • the upper electrode layer 450 may include a conductive material, such as aluminum (Al) or silver (Ag).
  • the upper electrode layer 450 may be formed by PVD, such as sputtering or thermal evaporation.
  • the substrate 400 on which a graphene structure is formed may be directly used to manufacture a solar cell.
  • the graphene structure since the graphene structure has transmittance and electrical conductivity, the graphene structure may also be used as a lower electrode layer. Also, if the graphene structure has an uneven surface, solar light may be scattered due to the uneven surface and refracted in various angles, thereby enabling more solar light to be absorbed by a solar cell.
  • a solar cell may be a substrate-type solar cell or a thin film-type solar cell.
  • a substrate-type solar cell includes a substrate formed of a semiconductor material such as silicon (Si), and a thin film-type solar cell includes a semiconductor thin film that is formed on a substrate such as a glass substrate.
  • Si silicon
  • a transparent electrode including a graphene structure according to an embodiment of the present invention is not limited thereto, and may also be used in a substrate-type solar cell.
  • the transparent electrode may be used as a protection layer for protecting an electrode layer and/or an electrode layer of a substrate-type solar cell.
  • the transparent electrode may be formed on a semiconductor substrate formed of, for example, single crystal or polycrystal silicon (Si).
  • FIG. 17 is a sectional view of another example of a solar cell using a graphene structure according to an embodiment of the present invention. In the present embodiment, a description presented with reference to FIG. 16 will not be provided herein.
  • the solar cell according to the present embodiment includes a substrate 500, a reflection prevention layer 505, a lower electrode layer 535, graphitizing catalyst particles 520P, a graphene layer 530, a semiconductor layer 540, and an upper electrode layer 550 sequentially disposed in this order on the substrate 500.
  • the substrate 500 may be a glass, quartz, or transparent plastic substrate.
  • the reflection prevention layer 505 may prevent a decrease in efficiency of the solar cell occurring when solar light is incident through the substrate 500 and then directly reflected to the outside instead of being absorbed by the semiconductor layer 540.
  • the reflection prevention layer 505 may include, for example, a silicon nitride (SiN) or a silicon oxide (SiO 2 ).
  • the lower electrode layer 535 may be a transparent conductive oxide (TCO), such as ZnO, SnO 2 , and ITO.
  • TCO transparent conductive oxide
  • the oxide materials may also have higher conductivity by including a small amount of impurities.
  • graphene structure used herein refers to a stack structure including the graphitizing catalyst particles 520P and the graphene layer 530, and the graphene structure may protect the lower electrode layer 535.
  • the lower electrode layer 535 may be protected from being damaged by an electrolytic solution. Since the graphene structure has, in addition to high transmittance, high conductivity, the graphene structure and the lower electrode layer 535 may form a double layer to function as an electrode.
  • the graphene structure may be formed by using the method described with reference to FIGS. 2 to 7.
  • the graphene structure may be formed directly on a stack structure including the substrate 500, the reflection prevention layer 505, and the lower electrode layer 535.
  • the graphene structure may be formed on a separate substrate and then transferred.
  • the semiconductor layer 540 may be formed on the graphene layer 530, and may have a pin structure including a p-type semiconductor layer 542, an i-type semiconductor layer 544, and an n-type semiconductor layer 546 stacked in this order.
  • Each of the p-type semiconductor layer 542, the i-type semiconductor layer 544, and the n-type semiconductor layer 546 may be single crystal silicon, polycrystal silicon, amorphous silicon, or a compound semiconductor.
  • the upper electrode layer 550 may include a conductive material formed of, for example, aluminum (Al) or silver (Ag).
  • the graphene structure has transmittance and electric conductivity
  • the graphene structure may be used as an electrode in combination with a lower electrode formed of ITO.
  • the graphene structure may protect the lower electrode layer.
  • a graphene structure and a transparent electrode including the graphene structure according to embodiments of the present invention have high electric conductivity and high transmittance.
  • graphene may be crystallized at a relatively low temperature by metallic contact of an amorphous carbon layer. Accordingly, much graphene may be manufactured by using a simple process.
  • graphene may be formed directly on a substrate for manufacturing a device.
  • a process in which graphene is separately manufactured and then separated and transferred to a substrate for fabricating a device is not needed, thereby simplifying a manufacturing process and preventing graphene damage that may occur when formed graphene is transferred.

Abstract

A method of forming graphene using an amorphous carbon layer and a solar cell including graphene formed by using the method. The method of forming graphene includes: forming an amorphous carbon layer on a substrate; forming a graphitizing catalyst layer on the amorphous carbon layer; and heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming a graphene layer on the graphitizing catalyst layer.

Description

GRAPHENE STRUCTURE, METHOD OF FORMING THE GRAPHENE STRUCTURE, AND TRANSPARENT ELECTRODE INCLUDING THE GRAPHENE STRUCTURE
The present invention relates to a method of forming graphene using an amorphous carbon layer, a graphene structure manufactured by using the method, and a transparent electrode including the graphene structure, and more particularly, to a method of forming graphene by metallic contact of an amorphous carbon layer, a graphene structure manufactured by using the method, and a transparent electrode including graphene manufactured by using the method.
Graphene refers to a two-dimensional and honeycomb-structural thin film that is composed of one one-carbon (C) atom sheet or a plurality of one-carbon (C) atom sheets. When carbon atoms are chemically bonded via sp2 hybrid orbitals, a two-dimensional carbon hexagonal plane is formed. Carbon has four outermost electrons, and during bonding, the four electrons are hybridized to take part in the bonding.
Examples of a carbon bond are an sp3 bond and an sp2 bond. When carbon atoms are bonded by only sp3 bonds, a square diamond is formed, and when carbon atoms are bonded by only sp2 bonds, graphite or graphene, that is, one layer of graphite, is formed. For example, electrons that are supposed to be present only in s orbitals or p orbitals are present in sp2 and sp3 hybrid orbitals, which are combinations of s orbitals and p orbitals. Since in an sp2 hybrid orbital, one electron is present in an s orbital and two electrons are present in a p orbital, the sp2 hybrid orbital includes a total of three electrons and an energy potential of each electron is the same. A hybrid orbital is more stable than an s orbital and a p orbital.
Graphene is a collection of carbon atoms each having a planar structure formed by sp2 bonds, and a thickness of one graphene sheet is equivalent to the size of one carbon atom, for example, about 0.3 nm. Graphene has a metallic property, conductivity in a layer direction, and excellent thermal conductivity. In addition, in graphene, charge carriers have high mobility, thereby enabling manufacturing of high-speed electronic devices. A graphene sheet has an electron mobility of about 20,000 to 50,000 cm2/Vs. Graphene has high dynamic rigidity and chemical stability, and semi-conductive and conductive properties, and a small thickness. Due to such characteristics, graphene may be easily used in manufacturing flat panel display devices, transistors, energy storage devices, and nano-sized electronic devices. Also, graphene may be easily used in manufacturing devices by using conventional semiconductor process techniques, and in particular, enables production of large-size highly integrated devices.
Graphene is getting more attention as an electron transport layer and as a transparent electrode of an electronic device operating based on a photovoltaic principle in which light is converted into electricity, such as a solar cell or a photo detector. Currently, indium thin oxide (ITO) is widely used as a transparent electrode of an electronic device. However, the price of indium (In), a major component of ITO, is increasing and chances of indium depletion are also increasing, thereby increasing manufacturing costs. In addition, ITO does not have flexibility and thus is not suitable for use in flexible devices.
The present invention provides a graphene structure having high transmittance and electrical conductivity and a transparent electrode using the graphene structure.
The present invention also provides a method of forming graphene in which graphene is formed directly on a substrate for fabricating a device, and a transparent electrode formed by using the method.
According to an aspect of the present invention, there is provided a method of forming graphene, the method including: forming an amorphous carbon layer on a substrate; forming a graphitizing catalyst layer on the amorphous carbon layer; and heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming a graphene layer on the graphitizing catalyst layer.
In embodiments of the present invention, the heat treatment, the graphitizing catalyst layer agglomerates.
In embodiments of the present invention, a stack structure including the graphitizing catalyst layer and the graphene layer has transmittance of 80% or higher.
In embodiments of the present invention, a stack structure including the graphitizing catalyst layer and the graphene layer has a sheet resistance of 10 Ω/□ to 50 Ω/□.
In embodiments of the present invention, the graphitizing catalyst layer includes a material for crystallizing amorphous carbon.
In embodiments of the present invention, the graphitizing catalyst layer includes at least one metal or metal alloy selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), and rhodium (Rh).
In embodiments of the present invention, the method may further include forming a graphitizing catalyst layer on the substrate and heat treating the graphitizing catalyst layer, before the forming of the amorphous carbon layer.
In embodiments of the present invention, the method may further include removing the substrate after the heat treatment.
In embodiments of the present invention, the method may further include removing the graphitizing catalyst layer after the heat treatment.
According to another aspect of the present invention, there is provided a method of forming graphene, the method including: forming a graphitizing catalyst layer on a substrate; forming an amorphous carbon layer on the graphitizing catalyst layer; and heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming an graphene layer on at least one of upper and lower surfaces of the graphitizing catalyst layer.
According to another aspect of the present invention, there is provided a graphene structure including: graphitizing catalyst particles; and a graphene layer on the graphitizing catalyst particles.
According to another aspect of the present invention, there is provided a transparent electrode including: graphitizing catalyst particles; and a graphene layer on the graphitizing catalyst particles.
The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
FIG. 1 is a sectional view of a graphene structure according to an embodiment of the present invention;
FIGS. 2 to 7 are sectional views for explaining a method of forming graphene according to an embodiment of the present invention;
FIG. 8 shows a transmission electron microscope (TEM) image of a graphene structure according to an embodiment of the present invention;
FIG. 9 shows Raman spectra of a graphene structure according to an embodiment of the present invention;
FIG. 10 is a graph showing sheet resistance measurement results of a graphene structure according to an embodiment of the present invention;
FIG. 11 is a graph showing transmittance measurement results of a graphene structure according to an embodiment of the present invention;
FIGS. 12 to 15 are sectional views for explaining a method of forming graphene according to another embodiment of the present invention;
FIG. 16 is a sectional view of an example of a solar cell using a graphene structure according to an embodiment of the present invention; and
FIG. 17 is a sectional view of another example of a solar cell using a graphene structure according to an embodiment of the present invention.
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description.
FIG. 1 is a sectional view of a graphene structure according to an embodiment of the present invention.
Referring to FIG. 1, graphitizing catalyst particles 120P and a graphene layer 130 may be formed on a substrate 100. The graphitizing catalyst particles 120P may be agglomerates formed by heat treating a thin-film type graphitizing catalyst layer.
The substrate 100 may be formed of a material that does not dissolve carbon and that does not cause carbon to diffuse. For example, the substrate 100 may be a glass substrate, a quartz substrate, or a sapphire substrate. Also, the substrate 100 may be a substrate including oxides.
The graphitizing catalyst particles 120P may be a material that is capable of crystallizing an amorphous carbon layer. Also, the graphitizing catalyst particles 120P may be a metallic material. For example, the graphitizing catalyst particles 120P may include at least one material selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), and rhodium (Rh).
The graphene layer 130 may include one graphene sheet or a plurality of graphene sheets. The graphene layer 130 may be formed on the graphitizing catalyst particles 120P, and may be a continuous film. The graphene layer 130 may have an uneven lower portion formed due to the graphitizing catalyst particles 120P and an even upper portion. Alternatively, the graphene layer 130 may also have an uneven upper portion formed due to the graphitizing catalyst particles 120P.
The stack structure of the graphitizing catalyst particles 120P and the graphene layer 130 is referred to as a graphene structure herein. The graphene structure may be used as a transparent electrode. The transparent electrode may be used in image sensors, solar cells, and light emitting devices, which require light transmittance and electrical conductivity. The transparent electrode may also be used as an electrode layer in various displays, such as a plasma display panel (PDP), a liquid crystal display (LCD), or a flexible display.
FIGS. 2 to 7 are sectional views for explaining a method of forming graphene according to an embodiment of the present invention.
Referring to FIG. 2, an amorphous carbon layer 110 may be formed on the substrate 100. The amorphous carbon layer 110 may be formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD), such as sputtering, molecular beam epitaxy (MBE), or thermal evaporation. The amorphous carbon layer 110 may be formed to have a thickness of a few nanometers or tens of nanometers, for example, a thickness of 2 nm to 30 nm.
Referring to FIG. 3, a graphitizing catalyst layer 120 may be formed on the amorphous carbon layer 110. The graphitizing catalyst layer 120 may include a metallic material that dissolves carbon. That is, the metallic material of the graphitizing catalyst layer 120 may be a material that dissolves carbon to form a carbon solution and crystallizes the amorphous carbon layer 110. For example, the graphitizing catalyst layer 120 may include at least one material selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), and rhodium (Rh).
The graphitizing catalyst layer 120 may be formed by PVD, CVD, atomic layer deposition (ALD), or electroplating. In addition, the formation of the graphitizing catalyst layer 120 and the formation of the amorphous carbon layer 110, which has been described with reference to FIG. 2, may be performed in-situ. The graphitizing catalyst layer 120 may be formed to have a thickness of a few nanometers to tens of nanometers, for example, 10 nm to 30 nm.
Referring to FIG. 4, the stack structure including the amorphous carbon layer 110 and the graphitizing catalyst layer 120 on the substrate 100 may be heat treated. The heat treatment may be performed at a temperature of 300℃ to 1200℃. When the heat treatment is performed at lower temperatures, carbon may not be dissolved and diffused, and when the heat treatment is performed at higher temperatures, the substrate 100 may be damaged. The heat treatment may be performed under an inert gas, for example, argon (Ar) gas atmosphere. In addition, hydrogen (H2) gas may be added thereto. For example, when argon gas and hydrogen gas are used in combination, a volumetric ratio of the argon gas to the hydrogen gas may be 2:1. The heat treatment process may be performed for, for example, 5 minutes to 10 minutes. The heat treatment process may be performed using a rapid thermal annealing (RTA) device or a typical furnace. After the heat treatment process is performed, the stack structure including the amorphous carbon layer 110 and the graphitizing catalyst layer 120 on the substrate 100 may be cooled. The cooling process may be a natural cooling.
Referring to FIG. 5, the graphene layer 130 may be formed when the amorphous carbon layer 110 is dissolved by and diffused into the graphitizing catalyst layer 120 during the heat treatment process. That is, during the heat treatment process, the amorphous carbon layer 110 is dissolved by the graphitizing catalyst layer 120 and thus carbon atoms are released. And, through the heat treatment process and the cooling process, the carbon atoms released by the graphitizing catalyst layer 120 are realigned in the graphitizing catalyst layer 120, thereby forming the graphene layer 130. The graphene layer 130 may be formed by crystallizing amorphous carbon atoms, wherein the crystallization may be induced by the graphitizing catalyst layer 120.
Referring to FIG. 6, after the heat treatment process, the graphitizing catalyst particles 120P and the graphene layer 130 may be formed.
The graphitizing catalyst particles 120P may be formed as a result of agglomeration of the graphitizing catalyst layer 120 of FIG. 5 in the heat treatment process. Sizes of the graphitizing catalyst particles 120P may differ according to a thickness of the graphitizing catalyst layer 120 and a heat treatment temperature.
The graphene layer 130 may be formed by crystallizing all the carbon atoms contained in the amorphous carbon layer 110. Accordingly, a thickness of the graphene layer 130 may be dependent upon a thickness of the amorphous carbon layer 110. If the thickness of the graphene layer 130 is small, as illustrated, the graphene layer 130 may have an uneven surface formed due to the graphitizing catalyst particles 120P. In another embodiment, as illustrated in FIG. 1, the graphene layer 130 may be formed to have an even surface.
Referring to FIG. 7, the substrate 100 may be removed. For example, the substrate 100 may be removed using an etchant. Thus, only the stack structure including the graphitizing catalyst particles 120P and the graphene 130 remains. According to an application device, the graphene structure may be placed on another substrate.
Although not illustrated in the drawings, additionally, the graphitizing catalyst particles 120P may be removed. The graphitizing catalyst particles 120P may be selectively removed by, for example, wet etching or dry etching. The removal process may be performed after the substrate 100 is removed or before the substrate 100 is removed.
In another embodiment, before the forming of the amorphous carbon layer 110 described with reference to FIG. 2, the graphitizing catalyst layer 120 may be additionally formed on the substrate 100. That is, the graphitizing catalyst layer 120 may be formed on upper and lower surfaces of the amorphous carbon layer 110. In another embodiment, after the graphitizing catalyst layer 120 is formed prior to the formation of the amorphous carbon layer 110, a heat treatment may be performed thereon. That is, after the graphitizing catalyst particles 120P are formed on the substrate 100 by a heat treatment, the amorphous carbon layer 110 is formed. By doing so, a contact area between carbon atoms and a graphitizing catalyst material may be increased.
There are various methods of forming a graphene layer. For example, a graphene layer may be formed by using a mechanical separation method in which graphene is separated from a graphite crystal or a silicon carbide (SiC) crystal thermal decomposition method.
As an example of a mechanical separation method, there is a scotch tape method as a fine mechanical separation method in which scotch tape is attached to and then separated from a graphite sample, thereby obtaining a graphene sheet separated from the graphite sample on a surface of the scotch tape. According to a silicon carbide (SiC) crystal thermal decomposition method, an SiC single crystal is heated to decompose SiC at a surface of the SiC single crystal to remove silicon (Si) and a graphene sheet is formed by remaining carbon atoms.
Also, a deposition process may be used to form graphene. For example, graphene is epitaxially grown on a sapphire substrate by MBE or CVD. In this regard, the epitaxial growth may be easily performed due to crystallographic compatibility between graphene and the sapphire substrate.
Since a graphene layer is formed by a heat treatment after an amorphous carbon layer and a graphitizing catalyst layer are deposited according to a method of forming graphene according to an embodiment of the inventive concept, large-size graphene may be formed using a simple process. In addition, since a graphene layer is formed directly on a substrate, transferring separately formed graphene onto a substrate for fabricating a device is not needed. Accordingly, the manufacturing process is simplified, and graphene damage, which may occur when graphene is transferred, may be prevented.
FIG. 8 shows a transmission electron microscope (TEM) image of a graphene structure according to an embodiment of the present invention.
Referring to FIG. 8, analysis results obtained using a TEM are shown. A stack structure including a graphene layer and a graphitizing catalyst used in the TEM analysis, that is, a graphene structure, was formed by using the method described with reference FIGS. 2 to 6. In this experiment, a graphene structure including an amorphous carbon layer having a thickness of 10 nm and a graphitizing catalyst layer formed of nickel (Ni) having a thickness of 10 nm was heat treated at a temperature of 500℃. The following drawings show results obtained using the graphene structure formed under the above conditions, unless the context clearly indicates otherwise.
The substrate 100 was a quartz substrate, and a dark region in FIG. 8 corresponds to a protection layer formed in a sample preparation process. The graphene layer 130 was formed on the substrate 100, and has a lattice fringe. It is known that a crystallization temperature of amorphous carbon is equal to or higher than 2000℃. However, according to a method of forming graphene according to an embodiment of the present invention, crystallization may be induced by metallic particles such as nickel (Ni) and may be performed at a temperature lower than the known crystallization temperature. In the present embodiment, it was confirmed that graphene was obtained by crystallizing carbon atoms at a temperature of 500℃ through a heat treatment process.
FIG. 9 shows Raman spectra of a graphene structure according to an embodiment of the present invention.
Referring to FIG. 9, Raman spectra according to heat treatment temperature are shown. Formation of graphene was confirmed in view of presence of the G peak (about 1580 cm-1) and the 2D peak (about 2690 cm-1). The G peak is a peak showing presence of an sp2 bond of graphene. As illustrated, it was confirmed that graphene was formed when the heat treatment was performed at a temperature equal to or higher than 400℃.
For reference, the D peak (about 1340 cm-1) is related to a grain size of graphene, and larger grains may have weaker peaks. In addition, a thickness of a graphene layer may be identified in view of a ratio of the G peak (about 1580 cm-1) and the 2D peak (about 2690 cm-1).
FIG. 10 is a graph showing sheet resistance measurement results of a graphene structure according to an embodiment of the present invention.
Referring to FIG. 10, sheet resistance (Rs) measurement results with respect to heat treatment temperature are shown. A sheet resistance of a graphene structure including graphitizing catalyst particles (see 120P of FIG. 1) may be in a range of about 10 Ω/□ to about 50 Ω/□. For example, if a heat treatment is performed at a temperature of 400℃, the graphene structure may have a sheet resistance of about 20 Ω/□.
In consideration that, amorphous carbon that is not heat treated has a specific resistance of 10,000 μΩ·cm and nickel (Ni) has a specific resistance of 30μΩ·cm, a sheet resistance of the graphene structure seems to be similar to that of nickel (Ni). That is, the sheet resistance of the graphene structure is similar to a sheet resistance of metal. Accordingly, it is confirmed that a graphene layer according to an embodiment of the present invention has high electrical conductivity.
FIG. 11 is a graph showing transmittance measurement results of a graphene structure according to an embodiment of the present invention. The transmittance analysis was performed using an ultraviolet (UV)-visible spectrophotometer, and in the analysis results, transmittance is represented by %.
Referring to FIG. 11, at a heat treatment temperature equal to or higher than 500℃, the transmittance is increased to 80% or more. In a visible light wavelength range of about 400 nm to 750 nm, the transmittance is about 75% or more.
For reference, although not illustrated, an amorphous carbon layer having a thickness of 10 nm has transmittance of about 57%. In addition, when only a nickel (Ni) layer is heat treated, the nickel layer has transmittance of nearly 100% and higher heat treatment temperatures lead to higher transmissibilities.
From the analysis results, it can be confirmed that a graphene structure according to an embodiment of the present invention has higher transmittance than an amorphous carbon layer. In addition, in consideration that heat treatment of metal results in high transmittance, it can be confirmed that nickel (Ni) particles as graphitizing catalyst particles (see 120P of FIG. 1) does not affect transmittance of the graphene structure.
FIGS. 12 to 15 are sectional views for explaining a method of forming graphene according to another embodiment of the present invention. In the present embodiment, a description presented with reference to FIGS. 2 to 6 will not be provided herein.
Referring to FIG. 12, a graphitizing catalyst layer 220 may be formed on a substrate 200. The graphitizing catalyst layer 220 may include a metallic material that dissolves carbon.
The graphitizing catalyst layer 220 may be formed by PVD, CVD, ALD, or electroplating. A thickness of the graphitizing catalyst layer 220 may be in a range of a few nanometers to tens of nanometers, for example, 2 nm to 30 nm.
Referring to FIG. 13, an amorphous carbon layer 210 may be formed on the graphitizing catalyst layer 220. The amorphous carbon layer 210 may be formed by PVD, such as sputtering or thermal evaporation. The amorphous carbon layer 210 may be formed to have a thickness of a few nanometers to tens of nanometers, for example, 10 nm to 30 nm.
Referring to FIG. 14, the stack structure including the graphitizing catalyst layer 220 and the amorphous carbon layer 210 on the substrate 200 may be heat treated. The heat treatment process may be performed at a temperature of 300℃ to 1200℃. The heat treatment may be performed under an inert gas, for example, argon (Ar) gas atmosphere. In addition, hydrogen (H2) gas may be added thereto. For example, when argon gas and hydrogen gas are used in combination, a volumetric ratio of the argon gas to the hydrogen gas may be 2:1. The heat treatment process may be performed for, for example, 5 minutes to 10 minutes. The heat treatment process may be performed using a rapid thermal annealing (RTA) device or a typical furnace. After the heat treatment process is performed, the stack structure including the amorphous carbon layer 210 and the graphitizing catalyst layer 220 on the substrate 200 may be cooled. The cooling process may be a natural cooling.
Referring to FIGS. 14 and 15, after the heat treatment process is performed, graphitizing catalyst particles 220P and a graphene layer 230 may be formed.
The graphitizing catalyst particles 220P may be formed as a result of agglomeration of the graphitizing catalyst layer 220 of FIG. 14 in the heat treatment process.
The graphene layer 230 may be formed when the amorphous carbon layer 210 is dissolved by and diffused into the graphitizing catalyst layer 220 during the heat treatment process. The graphene layer 230 may be formed by the graphitizing catalyst layer 220 inducing crystallization of amorphous carbon. The graphene layer 230 may be formed on upper and lower surfaces of the graphitizing catalyst layer 220. In another embodiment, the graphene layer 230 may be formed only one of the upper and lower surfaces of the graphitizing catalyst layer 220.
FIG. 16 is a sectional view of an example of a solar cell using a graphene structure according to an embodiment of the present invention.
A solar cell is a device in which solar light energy is converted into electric energy by using a semiconductor property. A solar cell includes basically a diode having a pn junction, and an operational principle thereof will now be described in detail. When solar light having energy greater than an energy band gap of a semiconductor is incident on a pn junction of a solar cell, electron-hole pairs are generated, and from among the electron-hole pairs, electrons migrate to an n layer and holes migrate to a p layer due to an electric field formed at the pn junction, thereby generating photovoltaic power between the p and n layers. If a load or system is connected to ends of a solar cell when photovoltaic power is generated, a current flows, thereby generating electric power.
Referring to FIG. 16, the solar cell according to the present embodiment includes a substrate 400, and graphitizing catalyst particles 420P, a graphene layer 430, a semiconductor layer 440, and an upper electrode layer 450 sequentially disposed in this order on the substrate 400.
The substrate 400 may be a glass, quartz, or transparent plastic substrate.
The term graphene structure used herein refers to a stack structure including the graphitizing catalyst particles 420P and the graphene layer 430, and the upper electrode layer 450 may be a transparent electrode. The graphene structure may be manufactured by using the method described with reference to FIGS. 2 to 6. The substrate 400 may also be a substrate that is used for forming the graphene structure.
The semiconductor layer 440 may be formed on the graphene layer 430, and may have a pin structure including a p-type semiconductor layer 442, an i-type semiconductor layer 444, and an n-type semiconductor layer 446 sequentially stacked in this order. Each of the p-type semiconductor layer 442, the intrinsic(i)-type semiconductor layer 444, and the n-type semiconductor layer 446 may be single crystal silicon, polycrystal silicon, amorphous silicon, or a compound semiconductor. The i-type semiconductor layer 444 is depleted by the p-type semiconductor layer 442 and the n-type semiconductor layer 446 and an electric field occurs in the i-type semiconductor layer 444. Holes and electrons generated by solar light are drifted due to the electric field and gather in the p-type semiconductor layer 442 and the n-type semiconductor layer 446, respectively.
The upper electrode layer 450 may include a conductive material, such as aluminum (Al) or silver (Ag). The upper electrode layer 450 may be formed by PVD, such as sputtering or thermal evaporation.
In a solar cell including a graphene structure according to an embodiment of the present invention, the substrate 400 on which a graphene structure is formed may be directly used to manufacture a solar cell. In addition, since the graphene structure has transmittance and electrical conductivity, the graphene structure may also be used as a lower electrode layer. Also, if the graphene structure has an uneven surface, solar light may be scattered due to the uneven surface and refracted in various angles, thereby enabling more solar light to be absorbed by a solar cell.
A solar cell may be a substrate-type solar cell or a thin film-type solar cell. A substrate-type solar cell includes a substrate formed of a semiconductor material such as silicon (Si), and a thin film-type solar cell includes a semiconductor thin film that is formed on a substrate such as a glass substrate. The present embodiment will be described with reference to a thin film-type solar cell. However, a transparent electrode including a graphene structure according to an embodiment of the present invention is not limited thereto, and may also be used in a substrate-type solar cell. For example, the transparent electrode may be used as a protection layer for protecting an electrode layer and/or an electrode layer of a substrate-type solar cell. In this regard, the transparent electrode may be formed on a semiconductor substrate formed of, for example, single crystal or polycrystal silicon (Si).
FIG. 17 is a sectional view of another example of a solar cell using a graphene structure according to an embodiment of the present invention. In the present embodiment, a description presented with reference to FIG. 16 will not be provided herein.
Referring to FIG. 17, the solar cell according to the present embodiment includes a substrate 500, a reflection prevention layer 505, a lower electrode layer 535, graphitizing catalyst particles 520P, a graphene layer 530, a semiconductor layer 540, and an upper electrode layer 550 sequentially disposed in this order on the substrate 500.
The substrate 500 may be a glass, quartz, or transparent plastic substrate.
The reflection prevention layer 505 may prevent a decrease in efficiency of the solar cell occurring when solar light is incident through the substrate 500 and then directly reflected to the outside instead of being absorbed by the semiconductor layer 540. The reflection prevention layer 505 may include, for example, a silicon nitride (SiN) or a silicon oxide (SiO2).
The lower electrode layer 535 may be a transparent conductive oxide (TCO), such as ZnO, SnO2, and ITO. In addition, the oxide materials may also have higher conductivity by including a small amount of impurities.
The term graphene structure used herein refers to a stack structure including the graphitizing catalyst particles 520P and the graphene layer 530, and the graphene structure may protect the lower electrode layer 535. For example, when the lower electrode layer 535 is formed and then electroplating is performed in a subsequent interconnection process, the lower electrode layer 535 may be protected from being damaged by an electrolytic solution. Since the graphene structure has, in addition to high transmittance, high conductivity, the graphene structure and the lower electrode layer 535 may form a double layer to function as an electrode.
The graphene structure may be formed by using the method described with reference to FIGS. 2 to 7. The graphene structure may be formed directly on a stack structure including the substrate 500, the reflection prevention layer 505, and the lower electrode layer 535. Alternatively, the graphene structure may be formed on a separate substrate and then transferred.
The semiconductor layer 540 may be formed on the graphene layer 530, and may have a pin structure including a p-type semiconductor layer 542, an i-type semiconductor layer 544, and an n-type semiconductor layer 546 stacked in this order. Each of the p-type semiconductor layer 542, the i-type semiconductor layer 544, and the n-type semiconductor layer 546 may be single crystal silicon, polycrystal silicon, amorphous silicon, or a compound semiconductor.
The upper electrode layer 550 may include a conductive material formed of, for example, aluminum (Al) or silver (Ag).
In a solar cell including a graphene structure according to an embodiment of the present invention, the graphene structure has transmittance and electric conductivity, the graphene structure may be used as an electrode in combination with a lower electrode formed of ITO. Alternatively, the graphene structure may protect the lower electrode layer.
A graphene structure and a transparent electrode including the graphene structure according to embodiments of the present invention have high electric conductivity and high transmittance.
According to a method of forming graphene according to an embodiment of the present invention, graphene may be crystallized at a relatively low temperature by metallic contact of an amorphous carbon layer. Accordingly, much graphene may be manufactured by using a simple process.
According to an embodiment of the present invention, graphene may be formed directly on a substrate for manufacturing a device. Thus, a process in which graphene is separately manufactured and then separated and transferred to a substrate for fabricating a device is not needed, thereby simplifying a manufacturing process and preventing graphene damage that may occur when formed graphene is transferred.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims (12)

  1. A method of forming graphene, the method comprising:
    forming an amorphous carbon layer on a substrate;
    forming a graphitizing catalyst layer on the amorphous carbon layer; and
    heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming a graphene layer on the graphitizing catalyst layer.
  2. The method of claim 1, wherein, in the heat treatment, the graphitizing catalyst layer agglomerates.
  3. The method of claim 1, wherein a stack structure comprising the graphitizing catalyst layer and the graphene layer has transmittance of 80% or higher.
  4. The method of claim 1, wherein a stack structure comprising the graphitizing catalyst layer and the graphene layer has a sheet resistance of 10 Ω/□ to 50 Ω/□.
  5. The method of claim 1, wherein the graphitizing catalyst layer comprises a material for crystallizing amorphous carbon.
  6. The method of claim 1, wherein the graphitizing catalyst layer comprises at least one selected from the group consisting of nickel (Ni), copper (Cu), cobalt (Co), ruthenium (Ru), iridium (Ir), iron (Fe), plutonium (Pt), palladium (Pt), rhodium (Rh), and an alloy thereof.
  7. The method of claim 1, before the forming of the amorphous carbon layer, further comprising:
    forming a graphitizing catalyst layer on the substrate; and
    heat treating the graphitizing catalyst layer.
  8. The method of claim 1, after the heat treatment, further comprising:
    removing the substrate.
  9. The method of claim 1, after the heat treatment, further comprising:
    removing the graphitizing catalyst layer.
  10. A method of forming graphene, the method comprising:
    forming a graphitizing catalyst layer on a substrate;
    forming an amorphous carbon layer on the graphitizing catalyst layer; an heat treating the amorphous carbon layer and the graphitizing catalyst layer to crystallize the amorphous carbon layer, thereby forming an graphene layer on at least one of upper and lower surfaces of the graphitizing catalyst layer.
  11. A graphene structure comprising:
    graphitizing catalyst particles; and
    a graphene layer on the graphitizing catalyst particles.
  12. A transparent electrode comprising:
    graphitizing catalyst particles; and
    a graphene layer on the graphitizing catalyst particles.
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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102774065A (en) * 2012-06-01 2012-11-14 中国科学院宁波材料技术与工程研究所 Amorphous carbon film with graphene structure and preparation method thereof
WO2014150586A1 (en) * 2013-03-15 2014-09-25 Solan, LLC Graphene manufacture using foundation materials with favored structures
WO2016066413A1 (en) * 2014-10-29 2016-05-06 Aixtron Se Method for separating a carbon structure from a seed structure
US9382118B2 (en) * 2014-11-11 2016-07-05 Hanwha Techwin Co., Ltd. Method of manufacturing graphene
US11127941B2 (en) 2019-10-25 2021-09-21 Lyten, Inc. Carbon-based structures for incorporation into lithium (Li) ion battery electrodes
US11127942B2 (en) 2019-10-25 2021-09-21 Lyten, Inc. Systems and methods of manufacture of carbon based structures incorporated into lithium ion and lithium sulfur (li s) battery electrodes
US11133495B2 (en) 2019-10-25 2021-09-28 Lyten, Inc. Advanced lithium (LI) ion and lithium sulfur (LI S) batteries
US11198611B2 (en) 2019-07-30 2021-12-14 Lyten, Inc. 3D self-assembled multi-modal carbon-based particle
US11309545B2 (en) 2019-10-25 2022-04-19 Lyten, Inc. Carbonaceous materials for lithium-sulfur batteries
US11342561B2 (en) 2019-10-25 2022-05-24 Lyten, Inc. Protective polymeric lattices for lithium anodes in lithium-sulfur batteries
US11398622B2 (en) 2019-10-25 2022-07-26 Lyten, Inc. Protective layer including tin fluoride disposed on a lithium anode in a lithium-sulfur battery
US11489161B2 (en) 2019-10-25 2022-11-01 Lyten, Inc. Powdered materials including carbonaceous structures for lithium-sulfur battery cathodes
US11508966B2 (en) 2019-10-25 2022-11-22 Lyten, Inc. Protective carbon layer for lithium (Li) metal anodes
US11539074B2 (en) 2019-10-25 2022-12-27 Lyten, Inc. Artificial solid electrolyte interface (A-SEI) cap layer including graphene layers with flexible wrinkle areas
US11631893B2 (en) 2019-10-25 2023-04-18 Lyten, Inc. Artificial solid electrolyte interface cap layer for an anode in a Li S battery system
US11735745B2 (en) 2021-06-16 2023-08-22 Lyten, Inc. Lithium-air battery
US11870063B1 (en) 2022-10-24 2024-01-09 Lyten, Inc. Dual layer gradient cathode electrode structure for reducing sulfide transfer

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101920718B1 (en) 2012-07-27 2018-11-21 삼성전자주식회사 Graphene device manufacturing apparatus and graphene device manufacturing method using the apparatus
KR101432970B1 (en) * 2012-07-29 2014-08-21 이장훈 Manufacturing method of graphen structure using carbon black
KR101984695B1 (en) 2012-08-29 2019-09-03 삼성전자주식회사 Graphene device and method of manufacturing the same
CN103193224B (en) * 2013-04-17 2015-07-08 苏州大学 Method for preparing graphene film on nonmetallic substrate at low temperature
KR101915206B1 (en) * 2014-11-11 2018-11-05 한화에어로스페이스 주식회사 Method for manufacturing graphene
US10816828B2 (en) 2016-11-02 2020-10-27 Samsung Electronics Co., Ltd. Multi-stack graphene structure and device including the same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050271574A1 (en) * 2004-06-03 2005-12-08 Jang Bor Z Process for producing nano-scaled graphene plates
US20060216222A1 (en) * 2002-10-21 2006-09-28 Jang Bor Z Process for nano-scaled graphene plates
KR20090026568A (en) * 2007-09-10 2009-03-13 삼성전자주식회사 Graphene sheet and process for preparing the same
KR20090065205A (en) * 2007-12-17 2009-06-22 삼성전자주식회사 Process for preparing graphene shell and graphene shell obtained by same process

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060216222A1 (en) * 2002-10-21 2006-09-28 Jang Bor Z Process for nano-scaled graphene plates
US20050271574A1 (en) * 2004-06-03 2005-12-08 Jang Bor Z Process for producing nano-scaled graphene plates
KR20090026568A (en) * 2007-09-10 2009-03-13 삼성전자주식회사 Graphene sheet and process for preparing the same
KR20090065205A (en) * 2007-12-17 2009-06-22 삼성전자주식회사 Process for preparing graphene shell and graphene shell obtained by same process

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* Cited by examiner, † Cited by third party
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WO2016066413A1 (en) * 2014-10-29 2016-05-06 Aixtron Se Method for separating a carbon structure from a seed structure
CN107001044A (en) * 2014-10-29 2017-08-01 艾克斯特朗欧洲公司 The method that carbon structure is separated from seed crystal structure
US10563300B2 (en) 2014-10-29 2020-02-18 Aixtron Se Method for separating a carbon structure from a seed structure
CN107001044B (en) * 2014-10-29 2020-10-27 艾克斯特朗欧洲公司 Method of separating carbon structures from seed structures
TWI718110B (en) * 2014-10-29 2021-02-11 德商愛思強歐洲公司 Method of separating carbon structure from seed structure
US9382118B2 (en) * 2014-11-11 2016-07-05 Hanwha Techwin Co., Ltd. Method of manufacturing graphene
US11198611B2 (en) 2019-07-30 2021-12-14 Lyten, Inc. 3D self-assembled multi-modal carbon-based particle
US11299397B2 (en) 2019-07-30 2022-04-12 Lyten, Inc. 3D self-assembled multi-modal carbon-based particles integrated into a continuous electrode film layer
US11398622B2 (en) 2019-10-25 2022-07-26 Lyten, Inc. Protective layer including tin fluoride disposed on a lithium anode in a lithium-sulfur battery
US11127941B2 (en) 2019-10-25 2021-09-21 Lyten, Inc. Carbon-based structures for incorporation into lithium (Li) ion battery electrodes
US11133495B2 (en) 2019-10-25 2021-09-28 Lyten, Inc. Advanced lithium (LI) ion and lithium sulfur (LI S) batteries
US11309545B2 (en) 2019-10-25 2022-04-19 Lyten, Inc. Carbonaceous materials for lithium-sulfur batteries
US11342561B2 (en) 2019-10-25 2022-05-24 Lyten, Inc. Protective polymeric lattices for lithium anodes in lithium-sulfur batteries
US11127942B2 (en) 2019-10-25 2021-09-21 Lyten, Inc. Systems and methods of manufacture of carbon based structures incorporated into lithium ion and lithium sulfur (li s) battery electrodes
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