Temperature-Dependent Photoluminescence Analysis of 1.0MeV Electron Irradiation-Induced Nonradiative Recombination Centers in n^+–p GaAs Middle Cell of GaInP/GaAs/Ge Triple-Junction Solar Cells

The effects of irradiation of 1.0 MeV electrons on the n^+–p GaAs middle cell of GaInP/GaAs/Ge triple-junction solar cells are investigated by temperature-dependent photoluminescence (PL) measurements in the 10–300 K temperature range. The appearance of thermal quenching of the PL intensity with increasing temperature confirms the presence of a nonradiative recombination center in the cell after the electron irradiation, and the thermal activation energy of the center is determined using the Arrhenius plot of the PL intensity. Furthermore, by comparing the thermal activation and the ionization energies of the defects, the nonradiative recombination center in the n^+–p GaAs middle cell acting as a primary defect is identified as the E5 electron trap located at E_\rm c-0.96 eV.