Proton Irradiation Damage in GaAs Single Crystals Examined for Solar Cells

Abstract

In this study, high-energy proton (0.5–2 MeV) irradiation damage in GaAs solar cells and single crystals was compared with 60Co γ-ray irradiation damage. The minority carrier diffusion length in proton-irradiated GaAs single crystals can be evaluated from the photovoltaic effect of solar cells. The damage rate in GaAs due to proton irradiation equivalent to that due to 60Co γ-ray irradiation was determined experimentally. The dependence of the damage rate on the proton energy and changes in the solar cell spectral reponse show that high-energy protons above 1 MeV produce uniform damage in a GaAs solar cell active layer, and most low-energy proton irradiation damage is confined within the surface layer. The behavior of proton irradiation damage in GaAs on annealing was also examined.