The Research On The Performance And Preparation Of The Cu₂ZnSnS₄（Se） Thin Film By Sputtering A Plurality Of Sulfide Targets

Cu₂ZnSnS₄（Se）（CZTS（Se））thin film solar cell possess two basic conditions for the solar cell with high conversion efficiency,one was direct band gap semiconductor,the other was that the best gap is range from 1.45 eV to 1.5eV for photovoltaic solar cell.The composition of Cu,Zn,Sn,S and Se for CZTS（Se）were rich in reserves,and with low price,at the same time with no pollution,etc.Because of this several original advantages for the CZTS（Se）thin film solar cell,this new energy materials were followed with interest by vast research staff.In this paper,the method of magnetron sputtering is used,the sulfur-containing precursor materials for CZTS（Se）thin film was prepared by sputtering several sulfur targets,the thin film was optimized after the sulfur-containing precursor go through from sulfurization（selenium）,and then the optimized CZTS（Se）was used to preparing a complete thin film solar cell device.The crystal structure,surface morphology,elemental composition,phase purity,electrical and optical properties of the CZTS（Se）thin film were characterized by using X ray diffraction（XRD）powder injection,Field Emission Scanning Electron Microscopy（FEI-SEM）,Energy Dispersive Spectrometer（EDS）,Raman Spectroscopy（Raman）,Holzer Tester（Hall）and Ultraviolet Visible spectrophotometer（UV-Vis）wind instrument,respectively.The electrical properties of the Cu₂ZnSnS₄（Se）（CZTS（Se））thin film solar cells were analyzed by I-V test.The main research contents and results of this paper:1.ZnS,SnS and CuS were used as targets,the precursor of the CZTS（Se）films with different stacking sequences were prepared by magnetron sputtering on the Mo glass.The CZTS thin film which broke off seriously from the substrate was prepared by the stack sequences of Glass / SnS / ZnS / CuS and Glass / SnS / CuS / ZnS,after a high temperature.For the stacking sequence of Glass/ ZnS / SnS / CuS and Glass/ZnS / CuS / SnS,the preparation of the two kinds of sulfur containing layers after annealing were found that CZTS thin films prepared by the stacking sequence Glass/ZnS / CuS / SnS with a good adsorption properties which after annealing the film did not fall off.However,the adsorption of Glass/ ZnS /CuS / SnS prepared by the sulfur containing layer was good,and the films were partially exfoliated after annealing.For sulfur containing preformed layer prepared by the stacking sequence of Glass /ZnS/SnS / CuS and Glass/ CuS /ZnS / SnS,after vulcanization annealing,the surface of the films prepared by these two kinds of laminates shows a large difference in the shedding.For the film of different stacking sequence in the broke off phenomenon,this was because relative density of the SnS was the biggest in this three target,and make a larger difference with the bottom Mo on the relative density,so when SnS was at bottom,the process of annealing lead the thin film is broke off from the substrate.At the same time,the relative density of SnS was the largest among the three kinds of the sulfur targets,and the preparation process of sulfur bearing layer should follow the principle of relative density from small to large.So Glass / ZnS / CuS / SnS was the best stacking sequence.2.By optimizing the best stacked sequential Glass/ZnS/CuS/SnS,the optimized sequence was Glass/ZnS/CuS/SnS/CuS.The effect of periodic thickness change on the quality of CZTS thin films in Glass/ZnS/CuS/SnS/CuS stacking order invariance was investigated.Namely,the total thickness of the film preform layer was fixed,and prefabricated layers with different cycles were prepared in accordance with the stacking sequence.It was found that the precursor with different cycles after sulfurization,CZTS thin films have good adhesion,without shedding phenomenon.The single cycle,double cycle and multi cycle preformed layers were annealed at 590 degrees at high temperature,The surface of CZTS film was smooth and compact,the crystal particle size was even,and there was no obvious impurity phase,andand meet the requirement of high efficient solar cell with the structure of the poor copper and rich zinc.3.The CZTS thin film absorption layer was chemically corroded by dilute hydrochloric acid and bromine methanol,the treated CZTS film absorbing layer was placed in an oven with air atmosphere for low temperature annealing,and the annealing time was set to 5 hours,10 hours,15 hours,20 hours and 25 hours,The effect of low temperature annealing on carrier concentration in CZTS films wasinvestigated.It was found that the carrier concentration of CZTS film decreases first and then increases with annealing time.After 15 hours of baking,the carrier concentration of the film material was reduced to 5.256 ×1017cm-3,based on which the battery device was prepared,and the conversion efficiency of the battery was3.6%4.CdS thin films were prepared by vacuum method and applied as a buffer layer on CZTS thin film solar cells.The effect of long time low temperature annealing on the performance of CZTS thin film solar cells was also compared.The study found that the key performance of CZTS thin films were improved after long time low temperature annealing,the short-circuit current,open circuit voltage and the fill factor have been improved.Finally,a CZTS thin film solar cell with a conversion efficiency of 3.6% was obtained.