High energy electron testing of silicon and GaAs/Ge solar cells

Silicon and GaAs/Ge solar cells were tested with 20 MeV, 40 MeV, and 60 MeV electrons to determine the displacement damage effects. Silicon cell degradation is linear with Non-Ionizing Energy Loss (NIEL) as reported in the literature. GaAs/Ge degradation was found to scale linearly with NIEL for the maximum power and as the square root of the NIEL for the open circuit voltage (Voc). The short circuit current degradation was found to be independent of electron energy.