Investigating the Interactions Between Arsenic and Selenium in CdSeTe/CdTe Solar Cells Using DFT Modelling

This study investigates the interactions between arsenic (As) and selenium (Se) in cadmium telluride (CdTe) solar cells using density functional theory (DFT). Two supercell models were employed to analyse dopant stability and clustering at difference scales. The results reveal a preference for As and Se to spatially separate, driven by local strain effects, resulting in Se patches. This anti-correlation behaviour provides critical insights into dopants interactions and their impact on bandgap grading and doping activation. The findings align with experimental observation of As-Se segregation and highlights potential challenges for achieving uniform bandgap grading in CdTe solar cells. This work highlights the importance of understanding dopant behaviour for optimising device performance. Future work will extend computational analysis to hybrid functionals, offering a comprehensive framework for guiding material design and fabrication processes.