Photoluminescence analysis of electron irradiation-induced defects in GaAs/Ge space solar cells

Photoluminescence measurements were carried out to investigate the degradation for GaAs/Ge space solar cells which were irradiated with 1.0, 1.8, and 11.5 MeV electrons with fluences up to 3 × 1015 cm−2. The product of the defect introduction rate and the minority carrier capture cross section by electron irradiation-induced defects was determined with photoluminescence radiative efficiency related to the non-radiative recombination lifetime. Then the cross section was acquired according to the relation between the defect introduction rate and the non-ionizing energy loss. Furthermore, the non-radiative recombination could be identified among all the detected defects by comparing the cross section of the minority carrier capture.