The Research On The Performance And Preparation Of The Cu₂ZnSnS₄ Thin Film By Sputtering Quaternary Compound Target

As a quaternary compound P-type semiconductor,CZTS have a kesterite structure similar to that of CIGS,and its constituent elements are nontoxic and abundant in the crust.The band gap is 1.5eV with a large optical absorption coefficient(>10⁴cm^-1)and a theoretical conversion efficiency of 32.2%.It is considered to be one of the best materials for thin film solar cells.The basic properties of CZTS materials have been reported deeply in analysis,but the fabrication of CZTS thin film solar cell devices is very difficult.The crystal quality of CZTS films and the lattice mismatch between different layers of solar cell devices are also the reasons of the low photoelectric conversion efficiency in addition to the existence of more secondary phases and defects in the materials themselves.In order to solve the problems mentioned above,we put forward the technical methods of improving the preparation process of thin film and optimizing the structure of solar cell device.The specific work is as follows:?1?CZTS thin films were prepared by single target sputtering.The effects of different annealing temperatures on the properties of the films were studied.The films were characterized and analyzed by using relevant test equipment.The results show that the films prepared at 360?for 30 minutes and then annealed at 500?for 50 min have a good crystalline quality and a smooth and compact surface.?2?The difference between in-situ annealing and conventional anneal films is studied.The results show that after sputtering CZTS thin films with uniform grain size and good adhesion between layers can be obtained by in-situ annealing.The element composition of the thin film is rich zinc and poor copper,and the band gap is 1.52eV,which is suitable for the absorption layer of CZTS solar cells.?3?A thin ZnO film was deposited between Mo electrode and CZTS absorption layer by sputtering and annealed at low annealing temperature at 450?.The experimental results show that this method can effectively inhibit the diffusion of S element in the absorption layer and reduce the formation of MoS₂.Thus it can reduce the series resistance of solar cell devices.?4?On the basis of CZTS thin films with good properties,Mo back electrode was prepared by magnetron sputtering;CdS buffer film was prepared by chemical bath depostion;intrinsic ZnO and Al doped ZnO window layer films were prepared by magnetron sputtering;Ni/Al electrode was prepared by evaporation.