GaAs Solar Cells Grown on Unpolished, Spalled Ge Substrates: Preprint

Conference · Sat Jun 02 04:00:00 EDT 2018

OSTI ID:1457222

Cavalli, Alessandro ^[1]; Johnston, Steven ^[1]; Sulas, Dana ^[1]; Simon, John D ^[1]; Schulte, Kevin L ^[1]; Packard, Corinne ^[1]; Young, David L ^[1]; Ptak, Aaron J ^[1]; Ley, Brett ^[2]

---

1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2. Colorado School of Mines

Decreasing the cost of single-crystal substrates by wafer reuse techniques has long been sought for III-V solar cells. Controlled spalling of III-V devices is a possible pathway for epitaxial liftoff, which would help reduce costs, but chemo- mechanical polishing after liftoff tends to limit the potential cost savings. 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 then grew GaAs solar cells by HVPE on the spalled Ge surface without any other surface treatment. We show a 12.8% efficient single-junction device, without anti-reflection coating, with quantum efficiency very close to identical devices grown by HVPE on non-spalled GaAs substrates. Demonstrating a high carrier collection on unpolished spalled wafers is a step toward reducing substrate-related liftoff and reuse costs.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1457222
• Report Number(s): NREL/CP-5900-71591
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
controlled spalling
epitaxial lift-off
gallium arsenide
germanium substrate
photovotaics
solar cells