Physical and optical properties of sprayed Cu2ZnSnS4 (CZTS) thin film: effect of Cu concentration

The crystallographic microstructural and optical properties of CZTS thin film have been investigated with influence of copper concentration in spray solution. The X-ray and Raman study carried out to the prepared CZTS thin films and attained pure kesterite phase. The results of microstructural properties such as crystallite size, d-spacing, microstrain, texture coefficient and standard deviation investigated. The prepared CZTS thin film shows very high optical absorption of the order of 10(5)cm(-1) in the visible region and the optical band gap energy varied between 1.45 and 1.47eV. This optical band gap tuning is most applicable for solar cells. By using the Wemple-DiDomenico (WDD) single oscillator model, the optical parameters were calculated such as single oscillator energy (E-0), dispersion energy (E-d), static refractive index (n(0)), etc. Large values of optical conductivity (sigma) give the promise to the solar cell application.