Ge Concentrator Cells for III-V Multijunction Devices

D. J. Friedman, J. M. Olson, S. Ward, T. Moriarty, K. Emery, Sarah Kurtz, A. Duda, R. R. King, H. L. Cotal, D. R. Lillington, J. H. Ermer, N. H. Karam

Research output: Contribution to conferencePaperpeer-review

21 Scopus Citations


We identify a failure mode due to a photoactive back contact for Ge concentrator solar cells. This problem manifests itself as a leveling off and subsequent decrease of open-circuit voltage (VOC) as the concentration increases above ∼20 suns. Correction of this problem yields a much improved Ge cell for which Voc increases in an almost ideal n=1 manner from 0.2 volts at one sun to 0.4 volts at 1400 suns. This cell's fill factor remains at or above its one-sun value up to 500 suns, confirming that this cell is fully suitable for high-concentration use. We show that solving the back-contact problem can significantly improve the high-concentration performance of GaInP/GaAs/Ge three-junction solar cells.

Original languageAmerican English
Number of pages3
StatePublished - 2000
Event28th IEEE Photovoltaic Specialists Conference, PVSC 2000 - Anchorage, United States
Duration: 15 Sep 200022 Sep 2000


Conference28th IEEE Photovoltaic Specialists Conference, PVSC 2000
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 2000 IEEE.

NREL Publication Number

  • NREL/CP-520-28913


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