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.

The 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.306