GaAs Solar Cells Grown on Unpolished, Spalled Ge Substrates

Alessandro Cavalli, Brett Ley, Steve Johnston, Dana Sulas, John Simon, Kevin L. Schulte, Corinne E. Packard, David L. Young, Aaron J. Ptak

Research output: Contribution to conferencePaperpeer-review

7 Scopus Citations


We spalled 2-inch Ge wafers using a Ni stressor layer and grew GaAs solar cells by hydride vapor phase epitaxy on the spalled Ge surface without other surface treatments. The controlled spalling procedure leaves behind arrest lines, which are parallel surface striations, perpendicular to the crack front, caused by the crack propagation repeatedly halting and restarting during the fracture. We show that small arrest lines do not significantly affect device performance, but larger lines act as regions for carrier recombination. We demonstrate a 12.8% efficient single-junction device, without anti-reflection coating, grown on a spalled surface containing arrest lines. The quantum efficiency of this device is similar to devices grown on non-spalled GaAs and Ge substrates.

Original languageAmerican English
Number of pages5
StatePublished - 26 Nov 2018
Event7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - Waikoloa Village, United States
Duration: 10 Jun 201815 Jun 2018


Conference7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018
Country/TerritoryUnited States
CityWaikoloa Village

Bibliographical note

See NREL/CP-5K00-71591 for preprint

NREL Publication Number

  • NREL/CP-5900-73680


  • Gallium Arsenide
  • photovoltaic cells
  • semiconductor growth
  • substrates


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