Abstract
Characteristic degradation curves for proton and electron induced degradation of triple junction (3J) and isotype Ga0.5In0.5P/GaAs/Ge solar cells were obtained. The displacement damage dose methodology in combination with a varying effective threshold energy for atomic displacement T-d,T-eff was used to analyze 3G28 and 3G30 3J cell data. The nonionizing energy loss (NIEL) was calculated analytically, and T-d,T-eff was explicitly introduced as a fit parameter. Using the GaAs NIEL in fitting the 3J degradation data, a T-d,T-eff of 21 eV was determined, whereas a T-d,T-eff of 36 eV was found using the Ga0.5In0.5P NIEL. In GaAs and Ga0.5In0.5P single junction cells, the effective threshold energies for atomic displacement of 22 and 34 eV were determined.