Investigation of degradation characteristics of electron irradiated GaInP/InGaAs/Ge solar cell by numerical simulation model

The degradation characteristics of lattice-matched (LM) GaInP/InGaAs/Ge solar cell under 1 MeV electron irradiation are numerically simulated using APSYS finite element analysis software and Essential Macleod Program. Main output parameters of solar cells are simulated based on the material energy band, minority carrier lifetime, and interface surface recombination velocity. The results show that the adverse effects of the displacement damages in solar cell materials induced by irradiation are the primary reasons for overall cell performance degradation. The minority carrier lifetime degraded mostly in InGaAs middle subcell after irradiation, and it became to the current-limiting unit in the end-of-life condition. The simulation results of the current-voltage curves and the external quantum efficiency spectra are well agreed with the irradiation experimental data under similar conditions. Furthermore, an approach to radiation hardening of LM GaInP/InGaAs/Ge solar cell by adjusting the base and emitter layer thickness in the InGaAs middle subcell is proposed based on this model.