Comparative study of As and Cu doping stability in CdSeTe absorbers

• Published in: Solar energy materials and solar cells Vol. 224; p. 111012
• Main Authors: Krasikov, Dmitry, Guo, Da, Demtsu, Samuel, Sankin, Igor
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2021
• Subjects: CdTe; Defects; Degradation; Doping; Solar cell; Stability; Solar cell; Degradation; Stability; CdTe; Doping; Defects
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2021.111012

The reasons behind the long-term degradation of Cu-doped CdTe thin-film solar cells have been a topic of discussion for almost two decades. Yet the underlying mechanisms of such degradation, especially interactions of Cu doping with Cl in high-performance CdSeTe devices, still lack detailed understanding. In this study, we provide a consistent theoretical analysis of the fundamental physics behind this phenomenon. We then identify the dominant device degradation mechanism that cannot be completely eliminated in Cu-doped chlorinated CdSeTe-based PV. Finally, we conclude that this key mechanism is absent in CdSeTe PV when using arsenic absorber doping, which explains the remarkable stability demonstrated by this new technology. Theoretical conclusions are supported by the results of accelerated life tests on Cu- and As-doped chlorinated CdSeTe cells. •Experimental and theoretical study of CdSeTe solar cell stability with Cu and As dopant.•The degradation of Cu-doped cells is explained using a defect chemistry model and a device model.•Low p-type doping and its long-term decay is a fundamental property of chlorinated Cu-doped CdTe absorbers.•Hole density and performance of chlorinated As-doped CdSeTe cells are stable after a 36-days test at 95oC.•The Cl-related defect complex causing degradation of Cu-doped devices is absent in the case of As doping.