Thickness optimization of CdS/ZnO hybrid buffer layer in CZTSe thin film solar cells using SCAPS simulation program

Abstract

In CZTSe thin film solar cell, CZTSe/CdS as absorber/buffer layer has been used and ZnO is used as a window layer. CdS as buffer layer have high efficiency but it is toxic due to cadmium. So to reduce the cadmium usage, a hybrid buffer layer of ZnO/CdS is proposed and the numerical study has been performed using SCAPS-1D simulator. The thickness of ZnO/CdS buffer layer has been optimized at ZnO-15 nm/CdS-65 nm, for maximum solar cell efficiency. The solar cell with hybrid buffer layer of ZnO/CdS exhibits more efficiency compared to the solar cell using only CdS or only ZnO as buffer layers. The solar cell efficiency variation with temperature has been studied for CdS, ZnO and CdS/ZnO buffer layer and observed that the variations are almost same for all the three layers.