Germanium solar cells grown by molecular beam epitaxy for lattice-matched, four-junction solar cells

Taizo Masuda, Joseph Faucher, Minjoo Larry Lee

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

Abstract

We demonstrate Ge junctions grown by molecular beam epitaxy (MBE) for lattice-matched, four-junction solar cells. Integrating a Ge bottom cell beneath a 1.9 eV InGaP/1.4 eV Ga(In)As/1.0 eV dilute nitride stack could enable ultra-high efficiencies in a single growth step. In this work, we successfully created Ge junctions by growth of homoepitaxial n-Ge emitters using As2 as a dopant on p-Ge wafers within a III-V MBE system. The growth and post anneal conditions are shown to strongly influence open-circuit voltage (Voc) in epitaxial Ge solar cells. Voc = 0.174 V was obtained without a window layer, which is comparable to the Voc of diffused Ge cells fabricated by metal-organic-vapor-phase-epitaxy for triple-junction solar cells.

Original languageEnglish (US)
Title of host publication2015 IEEE 42nd Photovoltaic Specialist Conference, PVSC 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479979448
DOIs
StatePublished - Dec 14 2015
Externally publishedYes
Event42nd IEEE Photovoltaic Specialist Conference, PVSC 2015 - New Orleans, United States
Duration: Jun 14 2015Jun 19 2015

Publication series

Name2015 IEEE 42nd Photovoltaic Specialist Conference, PVSC 2015

Other

Other42nd IEEE Photovoltaic Specialist Conference, PVSC 2015
Country/TerritoryUnited States
CityNew Orleans
Period6/14/156/19/15

Keywords

  • Germanium solar cell
  • MBE
  • four-junction
  • lattice-matched
  • photovoltaic cells

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

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