Temperature-dependent photoluminescence analysis of 1-MeV electron irradiation-induced nonradiative recombination centers in GaAs/Ge space solar cells

The effects of irradiation of 1-MeV electrons on p+–n GaAs/Ge solar cells have been investigated by temperature-dependent photoluminescence (PL) measurements in the temperature range of 10–290 K. The temperature dependence of the PL peak energy agrees well with the Varnish relation, and the thermal quenching of the total integrated PL intensity is well explained by the thermal quenching theory. Meanwhile, the thermal quenching of temperature-dependent PL confirmed that there are two nonradiative recombination centers in the solar cells, and the thermal activation energies of these centers are determined by Arrhenius plots of the total integrated PL intensity. Furthermore, the nonradiative recombination center, as a primary defect, is identified as the H3 hole trap located at Ev + 0.71 eV at room temperature and the H2 hole trap located at Ev + 0.41 eV in the temperature range of 100–200 K, by comparing the thermal activation and ionization energies of the defects.