Theoretical simulation of the degradation on GaAs sub-cell with different defects induced by 1MeV electron irradiation

The degradation on the GaAs sub-cell of GaInP/GaAs/Ge triple-junction solar cells caused by different types of defects induced by 1 MeV electron irradiation is studied by numerical simulation. The simulation model is introduced that includes geometric structure, material, doping concentration and electron irradiation defects. The degradation results of short-circuit current, open-circuit voltage, maximum power, conversion efficiency and external quantum efficiency versus different defects have been investigated, and the degradation mechanism is analyzed. The results show that when the defect concentration and carrier capture cross-section is the same, the related parameters degradation of GaAs sub-cell is more serious when the defect energy level is closed to the intrinsic Fermi energy level. Meanwhile, the degradation of related parameters induced by E2 (Ec-0.14 eV) and E5 (Ec-0.96 eV) defects are more serious than the degradation of related parameters induced by other defects. The research will provide a method to analyze the detailed degradation mechanism induced by electron irradiation and a reference to analyze the degradation of solar cells induced by space particles.