A study on the degradation of GaAs/Ge solar cells irradiated by <200Â keV protons

Damage effects in GaAs/Ge solar cells irradiated by <200 keV protons were studied by measuring their electrical properties and spectral response together with SRIM simulations. Proton energies of 40, 70 and 170 keV were chosen. Experimental results show that the short circuit current, open circuit voltage and maximum power decrease with increasing proton fluence. The degradation of the open circuit voltage is highest for 70 keV irradiation and lowest for 40 keV irradiation. The degradation of short circuit current decreases with increasing proton energy. According to SRIM simulations and spectral response analysis, the above changes in electrical properties are mainly related to damage in different regions of the solar cells.