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 journalArticle

4 Scopus citations

Abstract

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)
JournalIEEE Journal of Photovoltaics
DOIs
Publication statusAccepted/In press - Aug 10 2018

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Keywords

  • Band alignment
  • Doping
  • Heterojunctions
  • interface
  • Kelvin probe (KP) force microscopy
  • Microscopy
  • Molecular beam epitaxial growth
  • Photovoltaic cells
  • Silicon
  • silicon heterojunction (SHJ) solar cells
  • X-ray photoelectron spectroscopy

ASJC Scopus subject areas

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

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