1 MeV Electron Irradiation Effect and Damage Mechanism Analysis of GaInP/GaAs Heterojunction Solar Cells

This study explore the radiation damage effects on GaInP/GaAs heterojunction (HJT) solar cells when subjected to 1 MeV electron irradiation. Light I-V measurements show that V oc , J sc and Pmax of the cells exhibit a logarithmic degradation pattern with increasing electron irradiation fluence. Under identical irradiation conditions, the degradation of J sc is substantially less pronounced than that of V oc . Under the same conditions, the heterojunction cell shows better radiation resistance, mainly as its V oc degradation rate with fluence increase is lower than the homojunction cell. Spectral response analysis reveals that 1 MeV electron radiation mainly causes long-wave zone damage in the GaInP/GaAs HJT cells, which intensifies as irradiation fluence accumulates. Dark characteristic analysis indicates that both recombination and diffusion currents in the cells rise with increasing irradiation fluence, with recombination current dominating the dark current. Deep level transient spectroscopy tests show that 1 MeV electron irradiation introduces four defects (H 1 -H 4 ) in the cells, located at H 1 ( E v +0.717 eV)/H 4 * ( E v +0.744 eV), H 2 ( E v +0.369 eV), H 3 ( E v +0.282 eV) and H 4 ( E v +0.032 eV). Among these, the concentration H 1 of defects increases most drastically with fluence and directly correlates with the rapid degradation of cell performance under high fluence, making it the crucial factor responsible for the swift degradation of GaInP/GaAs HJT cells under high fluence 1 MeV electron irradiation.