High-efficiency heterojunction solar cells on crystalline germanium substrates

Bahman Hekmatshoar, Davood Shahrjerdi, Marinus Hopstaken

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


Stand-alone heterojunction (HJ) solar cells demonstrated on crystalline germanium (c-Ge) substrates are proposed for usage as the bottom cells of tandem-junction solar cells in various thin-film solar cell technologies. The emitter of the HJ solar cells is formed by growing thin layers of highly doped hydrogenated microcrystalline silicon (μc-Si:H) and further passivated by growing thin layers of hydrogenated amorphous silicon (a-Si:H). The μc-Si:H and a-Si:H layers are grown in the same reactor using plasma-enhanced chemical vapor deposition (PECVD) at temperatures close to 200°C. The quality of the c-Ge surface passivation by μc-Si:H and a-Si:H has a direct impact on the electrical performance of the HJ solar cells. Conversion efficiencies of 5.9% and 7.2% have been achieved for stand-alone c-Ge solar cells on n-type and p-type c-Ge substrates, respectively. These conversion efficiencies are well-comparable with the conversion efficiencies reported for conventional homojunction solar cells fabricated at temperatures as high as 600°C.

Original languageEnglish (US)
Title of host publicationOxide-Based Materials and Devices V
ISBN (Print)9780819499004
StatePublished - 2014
Event5th Annual Oxide Based Materials and Devices Conference - San Francisco, CA, United States
Duration: Feb 2 2014Feb 5 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


Other5th Annual Oxide Based Materials and Devices Conference
Country/TerritoryUnited States
CitySan Francisco, CA


  • Germanium
  • Heterojunctions
  • Plasma chemical vapor deposition
  • Solar cells
  • Surface passivation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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