Multijunction solar cells with subcell materials highly lattice-mismatched to germanium

D. C. Law, C. M. Fetzer, Richard King, P. C. Colter, H. Yoon, T. D. Isshiki, K. M. Edmondson, M. Haddad, N. H. Karam

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

11 Scopus citations


The performance of a series of metamorphic GalnP and GalnAs solar cells grown on Ge with lattice-mismatch ranging from 0% to 2.4% is reported, with emphasis on device structures with 0.5% and 1.6% mismatch. Dualjunction cells with moderately lattice-mismatched (0.2% and 0.5%) structures have already reached electrical performance comparable to lattice-matched devices, at about 26% efficiency under AM0, 1-sun condition. Development efforts to date on highly lattice-mismatched (16% mismatch) structures have resulted in 22.6% efficiency dual-junction cells, with many improvements still possible. Spectral response measurements reveal excellent quantum efficiency (QE) for metamorphic GalnP and GalnAs materials, with a measured internal QE of over 90%. The offsets between the bandgap voltage (Eg/q) and the open-circuit voltage (Voc) of GalnP and GalnAs metamorphic cells were kept below 550 mV and 450 mV, respectively. Experimental results indicate that lattice-mismatched GalnP/GalnAs dual-junction cells can achieve higher energy conversion efficiency than latticematched GalnP/GalnAs dual-junction solar cells.

Original languageEnglish (US)
Title of host publicationConference Record of the IEEE Photovoltaic Specialists Conference
Number of pages4
StatePublished - 2005
Externally publishedYes
Event31st IEEE Photovoltaic Specialists Conference - 2005 - Lake Buena Vista, FL, United States
Duration: Jan 3 2005Jan 7 2005


Other31st IEEE Photovoltaic Specialists Conference - 2005
Country/TerritoryUnited States
CityLake Buena Vista, FL

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Control and Systems Engineering


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