Kerf-less removal of Si, Ge, and III-V layers by controlled spalling to enable low-cost PV technologies

Stephen W. Bedell, Davood Shahrjerdi, Bahman Hekmatshoar, Keith Fogel, Paul A. Lauro, John A. Ott, Norma Sosa, Devendra Sadana

Research output: Contribution to journalArticlepeer-review


Kerf-less removal of surface layers of photovoltaic materials including silicon, germanium, and III-Vs is demonstrated by controlled spalling technology. The method is extremely simple, versatile, and applicable to a wide range of substrates. Controlled spalling technology requires a stressor layer, such as Ni, to be deposited on the surface of a brittle material, and the controlled removal of a continuous surface layer could be performed at a predetermined depth by manipulating the thickness and stress of the Ni layer. Because the entire process is at room temperature, this technique can be applied to kerf-free ingot dicing, removal of preformed p-n junctions or epitaxial layers, or even completed devices. We successfully demonstrate kerf-free ingot dicing, as well as the removal of III-V single-junction epitaxial layers from a Ge substrate. Solar cells formed on the spalled and transferred single-junction layers showed similar characteristics to nonspalled (bulk) cells, indicating that the quality of the epitaxial layers is not compromised as a result of spalling.

Original languageEnglish (US)
Article number6155057
Pages (from-to)141-147
Number of pages7
JournalIEEE Journal of Photovoltaics
Issue number2
StatePublished - 2012


  • Flexible photovoltaic (PV)
  • kerf-free
  • layer transfer
  • substrate reuse

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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