Optimizing CdTe Nanowall based Solar Cell Performance through Window Layer Material Selection

The impact of the window layer material on Nanowall-based solar cells employing CdTe technology has been investigated using the Technology Computer-Aided Design (TCAD) software Silvaco. The window layer materials that are most commonly discussed in the literature including Cd0.6Zn0.4Te, CdSe, CdS, Cd0.2Zn0.8S, ZnSe, ZnOS, CdSO, ZnO, and Mg0.2Zn0.8O have been selected for this study. The results show that window layer bandgap and band alignment with the absorber are critical. Higher bandgap materials like ZnO enhanced short-circuit current by improving window transparency, while unfavorable band offsets in MgZnO limited performance. Analysis of external quantum efficiency (EQE) confirmed the importance of window layer selection in mitigating blue loss and optimizing the solar cell response. The results offer insights for optimizing CdTe nanowall solar cells by strategically selecting the window layer material with the appropriate bandgap and band offsets.