10 MeV proton irradiation effects on GaInP/GaAs/Ge concentrator solar cells and their component subcells

Abstract

In this paper, the experimental results of a 10 MeV proton irradiation on concentrator GaInP/GaAs/Ge lattice-matched triple-junction solar cells and their corresponding subcells are examined. Electro-optical characterization such as external quantum efficiency, light and dark I-V measurements, is performed together with theoretical device modeling in order to guide the analysis of the degradation behavior. The GaInP (on Ge) and Ge cell showed a power loss between beginning of life and end of life of about 4% while the GaInP/GaAs/Ge and GaAs solar cells exhibited the highest damage measured of 12% and 10%, respectively for an irradiation fluence equivalent to an 8-years satellite mission in Low Earth Orbit. The results from single-junction solar cells correlate well with those of triple-junction solar cells. The performance of concentrator solar cells structures is similar to that of traditional space-targeted designs reported in literature suggesting that no special changes may be required to use triple junction concentrator solar cells in space.