Injection-enhanced annealing of InP solar-cell radiation damage

Abstract

This paper demonstrates that minority-carrier injection due to forward bias and light illumination under low current density and short-time injection conditions at room temperature can lead to enhanced recovery of radiation-induced defects in p-InP and radiation damage in InP n+-p junction solar cells. Deep-level transient spectroscopy analysis shows that the major defect centers H4 (EV +0.37 eV) and E2 (EC −0.19 eV) in p-InP exhibit injection-enhanced annealing which is a recombination-enhanced effect with a reduced activation energy of 0.133 eV. The marked recovery of the InP n+-p solar-cell radiation damage due to minority-carrier injection mainly results from recovery in minority-carrier diffusion length and decrease in recombination current. These mainly originate from the annihilation of the major defect centers H4 and E2 in the p-InP layer due to injection.