Microscopic Analysis of Interdiffusion and Void Formation in CdTe(1–x)Sex and CdTe Layers

Baines, Tom; Bowen, Leon; Mendis, Budhika G.; Major, Jonathan D.

Abstract

The use of CdSe layers has recently emerged as a route to improving CdTe photovoltaics through the formation of a CdTe(1–x)Sex (CST) phase. However, the extent of the Se diffusion and the influence it has on the CdTe grain structure has not been widely investigated. In this study, we used transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD) to investigate the impact of growing CdTe layers on three different window layer structures CdS, CdSe, and CdS/CdSe. We demonstrate that extensive intermixing occurs between CdS, CdSe, and CdTe layers resulting in large voids forming at the front interface, which will degrade device performance. The use of CdS/CdSe bilayer structures leads to the formation of a parasitic CdS(1–x)Sex phase. Following removal of CdS from the cell structure, effective CdTe and CdSe intermixing was achieved. However, the use of sputtered CdSe had limited success in producing Se grading in CST.

Citation

Baines, T., Bowen, L., Mendis, B. G., & Major, J. D. (2020). Microscopic Analysis of Interdiffusion and Void Formation in CdTe(1–x)Sex and CdTe Layers. ACS Applied Materials and Interfaces, 12(34), 38070-38075. https://doi.org/10.1021/acsami.0c09381

• Journal Article Type: Article
• Acceptance Date: Jul 28, 2020
• Online Publication Date: Aug 17, 2020
• Publication Date: Aug 26, 2020
• Deposit Date: Aug 24, 2020
• Publicly Available Date: Aug 25, 2020
• Journal: ACS Applied Materials and Interfaces
• Print ISSN: 1944-8244
• Electronic ISSN: 1944-8252
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 34
• Pages: 38070-38075
• DOI: https://doi.org/10.1021/acsami.0c09381
• Public URL: https://durham-repository.worktribe.com/output/1263194