Degradation fitting of irradiated solar cells using variable threshold energy for atomic displacement

Characteristic degradation curves for proton and electron induced degradation of triple junction (3J) and isotype Ga_0.5In_0.5P/GaAs/Ge solar cells were obtained. The displacement damage dose methodology in combination with a varying effective threshold energy for atomic displacement T _{d ,e f f} was used to analyze 3G28 and 3G30 3J cell data. The nonionizing energy loss (NIEL) was calculated analytically, and T _{d ,e f f} was explicitly introduced as a fit parameter. Using the GaAs NIEL in fitting the 3J degradation data, a T _{d ,e f f} of 21 eV was determined, whereas a T _{d ,e f f} of 36 eV was found using the Ga_0.5In_0.5P NIEL. In GaAs and Ga_0.5In_0.5P single junction cells, the effective threshold energies for atomic displacement of 22 and 34 eV were determined. Copyright © 2017 John Wiley & Sons, Ltd.