Metamorphic InGaP on GaAs and GaP for wide-bandgap photovoltaic junctions

J. Simon, S. Tomasulo, P. J. Simmonds, M. Romero, M. L. Lee

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


Metamorphic triple-junction solar cells can currently attain efficiencies as high as 41.1%. Using additional junctions could lead to efficiencies above 50%, but would require the development of a wide-bandgap (2.0-2.2 eV) material to act as the top layer. In this work we demonstrate wide-bandgap In yGa1-yP single junction solar cells grown on GaAs xP1-x via solid source molecular beam epitaxy. Tensile GaAsxP1-x buffers grown on GaAs exhibited asymmetric strain relaxation along with formation of faceted trenches, 100-300 nm deep running parallel to the [0-11] direction. Using smaller grading steps and higher substrate temperatures we minimized the faceted trench density and achieved symmetric strain relaxation. In comparison, compressively-strained graded GaAsxP1-x buffers on GaP showed nearly-complete strain relaxation of the top layers and no evidence of trenches. We subsequently grew InyGa1-yP solar cells on the GaAsxP 1-x buffers. Photoluminescence and transmission electron microscopy measurements gave no indication of CuPt ordering. Finally, we fabricated wide-bandgap InyGa1-yP solar cells and obtained V oc as high as 1.42 V for In0.39Ga0.61P with Eg =2.0 eV. Preliminary device results indicate that MBE-grown InyGa1-yP layers are promising candidates for future use as the top junction of a multijunction solar cell.

Original languageEnglish (US)
Title of host publicationProgram - 35th IEEE Photovoltaic Specialists Conference, PVSC 2010
Number of pages5
StatePublished - 2010
Externally publishedYes
Event35th IEEE Photovoltaic Specialists Conference, PVSC 2010 - Honolulu, HI, United States
Duration: Jun 20 2010Jun 25 2010

Publication series

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


Other35th IEEE Photovoltaic Specialists Conference, PVSC 2010
Country/TerritoryUnited States
CityHonolulu, HI

ASJC Scopus subject areas

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


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