CN103305790A - Preparation method of CdS/SiO2 nanometer transparent composite film - Google Patents

Abstract

The invention discloses a preparation method of a CdS/SiO2 nanometer transparent composite film, belonging to the technical field of preparation of semiconductor nanometer composite film materials. A CdS quantum dot nanometer composite film is prepared by radio frequency magnetron sputtering equipment through a CdS/SiO2 co-sputtering method. Compared with a chemical bath method, the sputtering method has the advantages of fastness, low temperature and the like and is capable of controlling the density and thickness of the composite film through power and time. The CdS quantum dot nanometer composite film is prepared by the sputtering method in the following two steps: firstly, carrying out radio frequency magnetron sputtering and depositing on an amorphous CdS/SiO2 composite film on an ultrahigh vacuum magnetron sputtering apparatus; annealing the deposited amorphous film and sulfur in N2 to form a polycrystalline film. SiO2 has a silicon hydroxyl and also has high transmissivity and low diffusivity, thereby fitting to surface decoration of nanometer composite film materials and protecting the CdS quantum dots and improving the luminous efficiency in the CdS/SiO2 nanometer composite film, and the composite film can be used as a conversion layer under a fluorescent solar concentrator, thereby having an extensive application prospect in the optoelectronic technology.

Description

A kind of CdS/SiO 2The preparation method of nanometer transparent laminated film

Technical field

The present invention relates to a kind of CdS/SiO of utilization ₂Cosputtering namely obtains CdS quantum dot nano transparent composite film material with radio-frequency sputtering, is to prepare CdS/SiO by RF magnetron co-sputtering ₂The method of ("/"--expression interface) laminated film belongs to semiconductor nano thin-film material preparing technical field.

Background technology

Magnetron sputtering become in the vacuum coating technology be most widely used, one of technology with the fastest developing speed.The film of sputter preparation has preferably homogeneity, repeatability and good Step Coverage, can accurately control simultaneously.Therefore more favourable for the insulating film of making fine size.The film of producing with radio-frequency magnetron sputter method has compact structure, purity advantages of higher.

CdS is a kind of typical II-VI family semi-conductor, and its energy gap is 2.42 eV, has wider energy gap.The CdS quantum dot is a kind of important semi-conductor nano particles then, has good optical property and surface modificability, can be widely used in the fields such as fluorescent mark material light emitting devices, laser, biological detection and analysis.The CdS quantum dot has wider absorbing wavelength band, higher emissive porwer and light stability preferably, not only can control emission and absorbing wavelength to satisfy different solar cells to Optical Absorption by regulating self size, and because its absorption spectrum and emission spectrum are overlapping less, enough Stokes shifts are arranged to reduce the heavily absorption of light beam, having increased the incident light subnumber, is a kind of more satisfactory fluorescence luminescent material.But because its material self-characteristic, CdS easily produces or generates surface state, thereby under the optical excitation condition, makes photo-generated carrier easily compound, has reduced quantum yield; In addition, CdS is limited in scope to photoresponse, has limited it in the application of photocatalysis field.

For in the fluorescent solar condensing apparatus, SiO ₂The surface has the silicon hydroxyl, thereby it is suitable for the finishing of material very much, in nano composite film, and SiO ₂Have very high transmissivity, very low scattered power is at CdS/SiO ₂In the nano compound film, play protection and reduced CdS quantum dot surface state, raising luminous efficiency.A large amount of materials that use mainly are a part of polymkeric substance at present, such as PMMA, PVP or Al ₂O ₃, CaF ₂Deng some mineral crystals.

The mode of traditional raising solar battery efficiency mainly is that the material and the structure that change battery are mated solar spectrum, and this mode has obtained significant development and has been expected to further breakthrough.Change an angle, in the situation that do not change device material and structure, based on the concept of spectral conversion, convert solar spectrum to frequency range that existing device has higher absorption, when improving battery conversion efficiency, can effectively reduce production costs.Introduce nano material, utilize its higher photochemical stability, same excitaton source excites the excellent optical properties such as polychromatic light, reaches the purpose of accurate spectral conversion.CdS quantum dot nano transparent composite film, as the nanometer transparent laminated film of economical and efficient, as the conversion layer under the fluorescent solar condensing apparatus, this type of nano compound film has obtained utilization.Have very high transmitance, the photoexcitation peak value of laminated film and its absorption peak exist a Stokes displacement energy to improve the spectrum efficiency of conversion, improve the assimilated efficiency of solar cell.

At present, the preparation method of CdS quantum dot nano transparent composite film mainly is the chemical bath method.Utilize radio-frequency magnetron sputter method to prepare CdS/SiO ₂The preparation method of nano compound film without definite patent report, and is better than the chemical bath method.

Summary of the invention

Therefore the objective of the invention is: a kind of employing CdS/SiO is provided ₂The cosputtering method prepares the CdS quantum dot composite material with radio-frequency sputtering, and cosputtering obtains CdS/SiO ₂The method for preparing the nanometer transparent laminated film.

Two-step approach is adopted in the preparation of CdS quantum dot nano film sample among the present invention: at first at high vacuum magnetron sputtering equipment radio-frequency magnetron sputter method deposited amorphous CdS/SiO ₂Laminated film; The noncrystal membrane that has deposited is again at N ₂In carry out anneal.

At first consider its Target Design, improve target utilization, film deposition speed and process stability for reaching, must carry out whole optimization design to sputtering system, the design of its hit (negative electrode) is the most key.The target design will be considered target surface Distribution of Magnetic Field, sedimentation rate and target utilization, also will consider the factors such as conduction, heat conduction, magnetic shielding, cooling, sealing and insulation.

Thereby relating to this technology needs the following technological process of tool and step:

1, CdS/SiO ₂Target:

The design of target such as Fig. 1, employing be circular SiO ₂Target (1) namely is quartzy (purity 99.99%) glass, pastes relatively and circular SiO with conductive resin in the above ₂The CdS wafer (2) of target center symmetry, and wafer is all on a concentric(al) circles, and adopting the wafer number is 4, also can be whole by sentiment; Make target on a radio-frequency power supply, 2 kinds of different materials of simultaneously sputter, and the CdS quantum dot is uniformly distributed in SiO ₂Interlayer can simply by increase and decrease CdS wafer (2) number, be regulated CdS and SiO simultaneously ₂Dutycycle;

2, thin film sputtering:

Sputtering target material by upper Fig. 1, consist of, formed by silica glass (purity 99.99%) and CdS wafer (2), see Fig. 1.

With the glass substrate behind the pretreatment cleaning, put into the sputter cavity.Sputter procedure is at room temperature carried out, and sputter procedure is at room temperature carried out, and the parameter of sputter is: range: 80mm; Argon flow amount: 10sccm, purity 99.999%; Base vacuum: 5 * 10 ^-4Pa; Sputtering pressure: 1Pa; Sputtering power: 100～180W; Sputtering time: 1～3h.

3, film thermal is processed:

In the CdS sputter procedure, because the difference of the aspects such as sputtering raste, nucleidic mass, heat of adsorption, Sulfur capacity easily loses.Sulphur in heat treatment process in the film is easily distillation also, therefore in the thermal treatment porcelain boat, added sulphur.The noncrystal membrane of deposition is placed in the porcelain boat with sulphur is parallel in right amount, sends into and carries out anneal in the stove.Annealing process adopts N ₂Atmosphere protection.Carry out anneal under certain temperature and the soaking time, temperature is 200 ℃～400 ℃, and the annealing soaking time is: 10min～60min.

, film characterization:

After Optimizing Technical and the parameter, to prepared CdS/SiO ₂Nano compound film has carried out sign and the performance analysis of UV, visible light light transmission rate of (pattern) XRD phase.

The present invention may be summarized to be: a kind of CdS/SiO ₂The preparation method of quantum dot nano transparent composite film is at first at SiO ₂Paste CdS wafer (2) on target (1) material, then, with the CdS/SiO of designed, designed ₂Target carries out r. f. magnetron sputtering amorphous CdS/SiO ₂Laminated film is again at N ₂Carry out anneal in the atmosphere, by Optimizing Process Parameters, to prepared CdS/SiO ₂Nano compound film has carried out relevant sign and performance analysis, shows that what produce is CdS quantum dot nano transparent composite film of fine quality.

Description of drawings

(1 is the CdS wafer to Fig. 1 target plane figure, and 2 is SiO ₂Target).

Fig. 2 CdS/SiO ₂The X-ray diffractogram of nanometer transparent laminated film.

CdS/SiO under the different sputtering powers of Fig. 3 ₂The UV, visible light light transmission rate collection of illustrative plates of nano compound film.

Embodiment

Embodiment

CdS quantum dot nano transparent film sample prepares with two-step approach: on the high vacuum magnetron sputtering equipment, with radio-frequency magnetron sputter method deposited amorphous CdS/SiO ₂Laminated film; The noncrystal membrane that has deposited is at N ₂Carry out anneal in the protection, specific as follows:

1, the cleaning of glass substrate:

Simple glass is carried out surface cleaning processing work, put into successively Triton (Triton X-100) aqueous solution, acetone soln, raw spirit solution and deionized water each ultrasonic 15 minutes, then glass substrate is dried.

2, Target Design and selection:

At circular SiO ₂Paste symmetrical CdS wafer (2) with conductive resin above the target (1), CdS wafer number is 4.Target is 99.99% by Φ 60mm * 5mm(purity) the CdS wafer of silica glass, Φ 5mm * 3mm consist of.

3, thin film sputtering:

Sputter procedure is at room temperature carried out, and sputtering target material is comprised of silica glass in above-mentioned 2 and CdS wafer, such as accompanying drawing 1; Glass substrate is put into before the sputter cavity, as above among the embodiment 1, institute's described method cleans oven dry.Sputter procedure is at room temperature carried out, and the parameter of sputter is:

Range: 80mm

Argon flow amount: 10sccm, purity 99.999%

Base vacuum: 5 * 10 ^-4Pa

Sputtering pressure: 1 Pa

Sputtering power: 180W

Sputtering time: 2 h

4, film thermal is processed:

The noncrystal membrane that sputtering sedimentation is complete, be placed on porcelain boat in parallel with an amount of sulphur sent into and carried out anneal in the stove.Annealing process adopts N ₂Atmosphere protection.Annealing temperature is 400 ℃, and the annealing soaking time is: 30min.

5, the sputter laminated film characterizes:

Under the optimization of sputter deposition craft condition and parameter, the CdS/SiO for preparing ₂Nano compound film has carried out the sign of X-ray diffraction (XRD), CdS is described, SiO ₂Phase exists, and the performance analysis of UV, visible light light transmission rate illustrates at 300-350nm to have higher transmitance.

The present invention is a kind of CdS/SiO ₂The novel preparation method of quantum dot nano transparent composite film if compare with chemical bath method etc., is characterized in: 1, and magnetron sputtering has fast, low temperature, can control CdS/SiO by power and time ₂The advantages such as laminated film density, thickness; 2, the CdS/SiO of designed, designed ₂The cosputtering target, employing be circular SiO ₂Target is pasted symmetrical CdS wafer with conductive resin again, can be on a radio-frequency power supply, and 2 kinds of different materials of simultaneously sputter, and the CdS quantum dot is uniformly distributed in SiO ₂Interlayer can simply by increase and decrease CdS wafer number, be regulated CdS and SiO ₂Dutycycle; 3, the CdS/SiO that adopts radio-frequency magnetron sputter method to obtain ₂The nanometer transparent laminated film, higher with the adhesion strength of substrate, have higher transmitance, have good optical property; 4, in film thermal is processed, adopt and add the sulphur source, can remedy the sulphur loss of film self in the annealing; 5, present device is simple, easy handling, good reproducibility.

Claims (3)

1. CdS/SiO ₂The preparation method of nanometer transparent laminated film is characterized in that film preparation employing two-step approach: on the high vacuum magnetron sputtering equipment, use radio-frequency magnetron sputter method, with amorphous CdS/SiO ₂Laminated film is deposited on and cleans on the rear glass substrate; Again with the noncrystal membrane that deposits, in N ₂Carry out anneal in the atmosphere, technological process specific as follows and step:

1) CdS/SiO ₂Target:

That adopt is circular high-purity Si O ₂Target (1) is pasted relatively and circular SiO with conductive resin in the above ₂The CdS wafer (2) of target center symmetry, and wafer is all on a concentric(al) circles, and adopting the wafer number is 4; And the CdS quantum dot is uniformly distributed in SiO as required ₂Interlayer makes target on a radio-frequency power supply, 2 kinds of different materials of simultaneously sputter;

2) thin film sputtering:

With the glass substrate behind the pretreatment cleaning, put into the sputter cavity, sputter procedure is at room temperature carried out, with above-mentioned CdS/SiO ₂Be target, the parameter of sputter is:

Range: 80mm; Argon flow amount: 10sccm, purity 99.999%; Base vacuum: 5 * 10 ^-4Pa; Sputtering pressure: 1 Pa; Sputtering power: 100～180W; Sputtering time: 1～3h;

3) film thermal is processed:

The noncrystal membrane of deposition is placed on and adds in the sulphur thermal treatment porcelain boat in stove, carries out anneal under certain temperature and the soaking time.

2. the preparation CdS/SiO described in according to claim 1 ₂The method of nanometer transparent laminated film is characterized in that the CdS/SiO that adopts to design ₂Target carries out cosputtering, can select different materials, high-purity Si O ₂Consist of with silica glass (purity 99.99%), increase and decrease simply CdS wafer (2) number simultaneously, regulate CdS and SiO ₂Dutycycle.

3. according to claim 1, the preparation CdS/SiO described in 2 ₂The method of nanometer transparent laminated film is characterized in that, the noncrystal membrane of deposition is at N ₂In the atmosphere protection, when annealing heat treatment process, sulphur and noncrystal membrane add in the porcelain boat, parallel thermal treatment, and temperature is 200 ℃～400 ℃, soaking time is: 10min～60min.

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