Progress of inverted metamorphic III-V solar cell development at Spectrolab

Hojun Yoon, Moran Haddad, Shoghig Mesropian, Jason Yen, Kenneth Edmondson, Daniel Law, Richard R. King, Dhananjay Bhusari, Andreea Boca, Nasser H. Karam

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

12 Scopus citations


Inverted metamorphic (IMM) solar cells based on III-V materials have the potential to achieve solar conversion efficiencies that are significantly higher than today's state of the art solar cells which are based on the 3-junction GaInP/GaInAs/Ge design. The 3J IMM device architecture based on (Al)GaInP/GaInAs/GaInAs, for example, allows for a higher voltage solar cell by replacing the low bandgap Ge (0.67 eV) from the conventional 3J structure with the higher bandgap (∼1 eV) metamorphic GaInAs. The inverted growth simply allows the lattice-matched junctions (i.e., (Al)GaInP/GaInAs) to be grown first on the growth substrate, thereby minimizing or shielding them from the defects that arise from the metamorphic layers. Spectrolab has demonstrated 30.5% AM0 efficiency based on the 3J IMM cell architecture grown on a Ge substrate, with Voc = 2.963V, Jsc = 16.9 mA/cm2, and FF = 82.5%. In addition, 4J IMM cells have been demonstrated with Voc of 4.072 V and AM0 efficiency approaching 25%. With additional development, demonstrating 33% AM0 efficiency is expected in the near future. However, the IMM devices demand more complex processing requirements than conventional solar cells, and we demonstrate the capability to fabricate large area solar cells from standard Ge solar cell substrates.

Original languageEnglish (US)
Title of host publication33rd IEEE Photovoltaic Specialists Conference, PVSC 2008
StatePublished - 2008
Externally publishedYes
Event33rd IEEE Photovoltaic Specialists Conference, PVSC 2008 - San Diego, CA, United States
Duration: May 11 2008May 16 2008

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371


Other33rd IEEE Photovoltaic Specialists Conference, PVSC 2008
Country/TerritoryUnited States
CitySan Diego, CA

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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