Understanding Performance Limitation of Cu2CdSnS4 as Photoactive Layer: Physics of Defect States and Recombination Mechanisms

Abstract

There is a plethora of thin-film photovoltaic materials like CIGS, CIGSSe, CZTS, CZTSSe, etc. that are currently under research and are suitable for commercial use. In this study, a Cu2CdSnS4 (CCdTS) based thin-film solar cell is simulated using SILVACO TCAD to extract its optical and electrical properties such as efficiency, electric field, short circuit current, quantum efficiency, etc. The device is also optimized by variation of such physical parameters as thickness, doping concentration and material defects of the absorber layer. A remarkable efficiency of 21.2% is reached under the condition of defect absence, whereas an efficiency of 7.5% is obtained for the defect presence in the absorber layer. Changes in behavior of the solar cell with material defects following Gaussian and Tail type distribution are also analyzed and corresponding conclusions are drawn.