Research Of CZTSSe Thin Film Prepared By Evaporation

The copper zinc tin sulfur selenium（Cu₂ZnSn（S,Se）₄,referred to CZTSSe）thin film compared with copper indium gallium selenide（CIGS）has a similar crystal structure,retains the excellent properties of CIGS thin film.The band gap of P type semiconductor material with direct band gap can be adjusted from 1.0 to 1.5ev at room temperature and covering the optimum band gap range.It is an ideal material tosubstitute CIGS thin films because of its abundant element composition and no-toxic,non-polluting characteristics.At present,the prepare methods of CZTSSe thin films are vacuum and non vacuum and the conversion efficiency is up to 32%³4%,which is higher than CIGS of 25%³0%while the maximum efficiency of CZTSSe thin film solar cell is a kind of non vacuum hydrazine solution spin coating then at high temperature with sulfur compound process and the conversion efficiency has reached 12.6%but lower than theory.In this paper,CZTSSe thin films were prepared by vacuum evaporation method and the properties of thin films at different processes were studied under the condition of stoichiometric ratio.The main results are as follows:（1）Research low temperature and high temperature of CZTSSe thin films prepared by one-step method.The morphology of the stoichiometric film is prepared smoothly at the substrate temperature of 500℃firstly,the disadvantage of the film is that chemical reaction is incomplete and the phase is impurity.When substratetemperature reach to 595℃,the stoichiometric film shows semi circular,for which anti steam is serious and CZTSSe decomposes to a certain extent,the impurity phase still exists.（2）Research two step to prepare CZTSSe film by low temperature fistly then at a high temperature.Firstly,stoichiometric film is prepared at the substrate temperature of 500℃and substrate temperature increased to 595℃rapidly then increase SnS and Se temperature and co-evaporated SnS,Se and ZnS,therefore an excellent Cu rich Zn poor absorbing layer film of CZTSSe was obtained.（3）The effect of post annealing on the properties of thin films was studied and the best temperature is 550℃as well as the optimum annealing atmosphere is S atmosphere.（4）Research low temperature then doped Sn to prepare CZTSSe thin film.