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

There is a plethora of thin-film photovoltaic materials like copper indium gallium sulfur (CIGS), CIGS-Selenium (CIGSSe), Cu2ZnSnS4 (CZTS),
$\text {Cu}_{{2}}\text {ZnSn} (\text {S}_{x}, \text {Se}_{{1}-{x}})_{{4}}$
(CZTSSe), and so on 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 technology computer-aided design (TCAD) to extract its optical and electrical properties such as efficiency, electric field (EF), short circuit current, quantum efficiency, and so on. The device is also optimized by variations in physical parameters such 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 the efficiency of 7.5% is obtained for the defect present in the absorber layer. Changes in the behavior of the solar cell with material defects following Gaussian- and tail-type distribution are also analyzed and corresponding conclusions are drawn.