Spectral response of InP/Si solar cells irradiated to high proton fluences

InP/Si solar cells have been irradiated with 3 MeV protons to very large fluences where carrier removal, instead of decreases in minority carrier diffusion length, dominates the radiation response. In this regime, radiation-induced expansion of the base depletion width causes I/sub sc/ to increase above the pre-irradiation level before falling catastrophically to zero. Current-voltage (IV), capacitance-voltage (CV), quantum efficiency (QE), and electrochemical capacitance-voltage (ECV) profiling measurements are presented.