Effect of Annealing on Physical Properties of Cu۲ZnSnS۴ (CZTS) Thin Films for Solar Cell Applications

Cu۲ZnSnS۴ (CZTS) thin films were prepared by directly sputteringCu (In,Ga)Se۲ quaternary target consisting of (Cu: ۲۵%, Zn: ۱۲.۵%, Sn; ۱۲.۵%and S: ۵۰%). The composition and structure of CZTS layers have beeninvestigated after annealing at ۲۰۰ ۰C, ۳۵۰ ۰C and ۵۰۰ ۰C under vacuum. Theresults show that recrystallization of the CZTS thin film occurs and increasingthe grain size with a preferred orientation in the (۱۱۲) direction was obtained. TheRaman spectra showed the existence of crystalline CZTS phase after annealing.Optical transmission spectra were recorded within the range ۳۰۰-۹۰۰ nm. Theenergy band gap (Eg) of the CZTS thin films was calculated before and afterannealing from the transmittance spectra using Beer-Lambert’s law. Results showthat Eg is dependent on the annealing temperature. The optical band gap of CZTSalso varied from ۱.۵۷ eV to ۱.۳۱ eV with increase in the annealing temperaturefrom ۲۰۰ ۰C min to ۵۰۰ ۰C.

کلیدواژه ها:

CZTS ، Magnetron Sputtering ، Optical Properties ، Solar Cells