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

•Pmax reduces 4% from BOL to EOL in GaInP/Ge and Ge and 10% for GaAs solar cells.•The 3J GaInP/GaAs/Ge cell exhibited a 12% power loss between BOL and EOL.•TCAD modeling is used to explain the losses in GaAs solar cells (most damaged cell).•The results from 1J solar cells correlate well with those of 3J solar cells.

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.

Graphical abstractThe experimental results of a 10 MeV proton irradiation on concentrator GaInP/GaAs/Ge lattice-matched triple-junction solar cells and their corresponding component subcells are examined. The analysis has been performed by means of in-situ and ex-situ electrical and optical characterization such as external quantum efficiency, dark and light I-V curves, deep-transient spectroscopy, among others. The results exhibit that GaInP (on Ge) and Ge cell showed an absolute 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. A single-defect model can reproduce the degradation damage observed on bulk and perimeter of GaAs solar cells for the accumulated fluences used here. The results from single-junction solar cells correlate well with those of triple-junction solar cells.Download high-res image (306KB)Download full-size image