Study of the interface in a GaP/Si heterojunction solar cell

Rebecca Saive, Hal Emmer, Christopher T. Chen, Chaomin Zhang, Christiana Honsberg, Harry Atwater

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


We have investigated the GaP/Si heterojunction interface for application in silicon heterojunction solar cells. We performed X-ray photoelectron spectroscopy (XPS) on thin layers of GaP grown on Si by metal organic chemical vapor deposition and molecular beam epitaxy. The conduction band offset was determined to be 0.9 ± 0.2 eV, which is significantly higher than predicted by Anderson's rule (0.3 eV). XPS also revealed the presence of Ga-Si bonds at the interface that are likely to be the cause of the observed interface dipole. Via cross-sectional Kelvin probe force microscopy (x-KPFM), we observed a charge transport barrier at the Si/GaP interface which is consistent with the high-conduction band offset determined by XPS and explains the low open-circuit voltage and low fill factor observed in GaP/Si heterojunction solar cells.

Original languageEnglish (US)
Article number8434086
Pages (from-to)1568-1576
Number of pages9
JournalIEEE Journal of Photovoltaics
Issue number6
StatePublished - Nov 2018


  • Band alignment
  • Kelvin probe (KP) force microscopy
  • X-ray photoelectron spectroscopy
  • interface
  • silicon heterojunction (SHJ) solar cells

ASJC Scopus subject areas

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


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