Numerical investigation on the role of ZnTe back surface layer in an efficient CuInS2 thin film solar cell

Abstract

This paper presents the modeling and numerical inspection of an efficient CuInS2-based n-CdS/p-CuInS2/p+-ZnTe thin film solar cell applying the SCAPS-1D simulator. The various parameters used in the simulation have been obtained from existing literature. The optimization of the device has considered the width, doping concentration, and defect density of individual layer. The optimized standalone CuInS2 device shows an efficiency of 16.83%. Addition of ZnTe in the device gives an impressive efficiency of approximately 28.67%, having a current density, JSC of 25.58 mA cm−2, a VOC of 1.25 V, and an FF of 89.12%. The superior VOC is a result of the increased built-in potential formed at the hetero-interfaces of the device and the decrease in surface recombination velocity by back surface field effect in the ZnTe layer. The highest JSC is ascribed to the enhancement of the absorption of vis-infrared photons by back surface field (BSF) effect in the ZnTe layer. These findings demonstrate the potential for manufacturing high efficiency CuInS2-based thin film solar cells in the future.