Effects of 1.0–11.5 MeV Electron Irradiation on GaInP/GaAs/Ge Triple-junction Solar Cells for Space Applications

GaInP/GaAs/Ge triple-junction solar cells are irradiated with 1.0, 1.8, and 11.5 MeV electrons with fluence ranging up to 3×10¹⁵, 3×10¹⁵, and 3×10¹⁴ cm^?2, respectively. Their performance degradation effects are analyzed by using current-voltage characteristics, spectral response measurements, and electron irradiation-induced displacements. The degradation rates of the maximum power and the spectral response of the solar cells increase with the electron fluence, and also increase with the increasing electron energy. It is observed that the spectral response of the GaAs middle cell degrades more significantly than that of the GaInP top cell.