Variation of Quantum Efficiency in CZTSSe Solar Cells with Temperature and Bias Dependence by SCAPS Simulation

Abstract

The quantum efficiency of CZTSSe (copper zinc tin sulphur selenium) thin film solar cells is numerically simulated at different temperatures and under a set of bias conditions about the efficiency limiting factors. A systematic methodology is developed and integrated into the proposed model to simulate the characteristics in the quantum efficiency. The proposed model is demonstrated with respect to an ideal device model under a set of bias conditions to selectively deactivate performance limiting parameters under light and voltage biased conditions. Under particular wavelength regions and bias conditions, a particular type of defects near the heterojunction interface significantly impact the carrier collection of devices. This deep acceptor type defect distribution is located in the band of +/-0.3 eV from the midgap. These defect states influence CZTSSe spectral responses of red and IR light wavelength regions in quantum efficiency caused by affected depletion width toward the back contact. Therefore, the quantum efficiency of CZTSSe devices is altered disproportionally at biased conditions.