GaAs Solar Cells with High Carrier Collection Grown on Unpolished, Spalled Ge Substrates: Preprint
Decreasing the cost of single-crystal substrates has long been sought for III-V solar cells. Controlled spalling is a possible pathway for epitaxial liftoff, which would help reduce costs, but chemo-mechanical polishing after liftoff tends to limit the impact. Growth on an unpolished spalled surface would be an additional step toward lower costs, but it is crucial to show high efficiency solar cell devices on these unprocessed substrates. In this study, we spalled 2 inch Ge wafers using a Ni stressor layer, and GaAs solar cells are grown by HVPE on the spalled Ge surface without any other surface treatment. We show a 12.8% efficient device, without anti-reflection coating, with equivalent quantum efficiency as identical devices grown by HVPE on non-spalled GaAs substrates. Demonstrating a high carrier collection on unpolished spalled wafers is the first step toward reducing substrate-related liftoff and polishing costs.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1472238
- Report Number(s):
- NREL/CP-5J00-70851
- Resource Relation:
- Conference: Presented at the 2018 World Conference on Photovoltaic Energy Conversion (WCPEC-7), 10-15 June 2018, Waikoloa, Hawaii
- Country of Publication:
- United States
- Language:
- English
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