Device and material characteristics of GalnP solar cells grown on Ge substrates by molecular beam epitaxy

Taizo Masuda, Joseph Faucher, Paul J. Simmonds, Kenichi Okumura, Minjoo Larry Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We investigated the characteristics of GalnP solar cells grown directly on Ge substrates by molecular beam epitaxy (MBE). For comparison, GaAs solar cells were also grown on Ge substrates using similar initiation conditions. Compared to cells on GaAs, large degradation in open-circuit voltage (Voc) and short-circuit current density (Jsc) were observed in GaInP/Ge cells, while only small reductions were observed for GaAs/Ge. Transmission electron microscopy reveals an extremely high threading dislocation density (TDD) in the 109 cm-2 range in GaInP/Ge, four orders of magnitude larger than that of GaAs/Ge, despite the minimal lattice mismatch in both cells. GaInP/Ge initiation is far more challenging than GaAs/Ge initiation by MBE, and a homoepitaxial Ge layer will likely be necessary to obtain high-quality films.

Original languageEnglish (US)
Title of host publication2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages2280-2284
Number of pages5
ISBN (Electronic)9781509056057
DOIs
StatePublished - 2017
Externally publishedYes
Event44th IEEE Photovoltaic Specialist Conference, PVSC 2017 - Washington, United States
Duration: Jun 25 2017Jun 30 2017

Publication series

Name2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017

Other

Other44th IEEE Photovoltaic Specialist Conference, PVSC 2017
Country/TerritoryUnited States
CityWashington
Period6/25/176/30/17

Keywords

  • Four-junction
  • GaInP solar cell
  • Germanium substrate
  • Lattice-matched
  • MBE

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

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