Recent progress of spectrolab high-efficiency space solar cells

Daniel C. Law, J. C. Boisvert, E. M. Rehder, P. T. Chiu, S. Mesropian, R. L. Woo, X. Q. Liu, W. D. Hong, C. M. Fetzer, S. B. Singer, D. M. Bhusari, K. M. Edmondson, A. Zakaria, B. Jun, D. D. Krut, R. R. King, S. K. Sharma, N. H. Karam

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

1 Scopus citations


Recent progress in III-V multijunction space solar cell has led to Spectrolab's GaInP/GaAs/Ge triple-junction, XTJ, cells with average 1-sun efficiency of 29% (AM0, 28?C) for cell size ranging from 59 to 72-cm2. High-efficiency inverted metamorphic (IMM) multijunction cells are developed as the next space solar cell architecture. Spectrolab's large-area IMM3J and IMM4J cells have achieved 33% and 34% 1-sun, AM0 efficiencies, respectively. The IMM3J and the IMM4J cells have both demonstrated normalized power retention of 0.86 at 5x1014 e-/cm2 fluence and 0.83 and 0.82 at 1x1015 e-/cm2 fluence post 1-MeV electron radiation, respectively. The IMM cells were further assembled into coverglass-interconnect-cell (CIC) strings and affixed to typical rigid aluminum honeycomb panels for thermal cycling characterization. Preliminary temperature cycling data of two coupons populated with IMM cell strings showed no performance degradation. Spectrolab has also developed semiconductor bonded technology (SBT) where highperformance component subcells were grown on GaAs and InP substrates separately then bonded directly to form the final multijunction cells. Large-area SBT 5-junction cells have achieved a 35.1% efficiency under 1-sun, AM0 condition.

Original languageEnglish (US)
Title of host publicationNanophotonics and Macrophotonics for Space Environments VII
StatePublished - Nov 29 2013
Externally publishedYes
Event7th Nanophotonics and Macrophotonics for Space Environments Conference, NMSE 2013 - San Diego, CA, United States
Duration: Aug 25 2013Aug 27 2013

Publication series

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


Other7th Nanophotonics and Macrophotonics for Space Environments Conference, NMSE 2013
Country/TerritoryUnited States
CitySan Diego, CA


  • III-V Multijunction
  • Inverted Metamorphic
  • Semiconductor Bonding Technology
  • Space Solar Cells

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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