InP substrates and epitaxial layers of different carrier concentrations were exposed to electron (3, 8 MeV) and gamma (up to 3, 8 MeV) radiation in distinct experiments. Photoluminescence (PL) measurements showed that highly doped substrates presented large full width at half maximum of PL peak due ro overlapping of donor impurity levels with the conduction band, a phenomenon which was not observed in undoped layer. Both highly doped substrates and undoped epitaxial layers showed a significant decrease in PL intensity after irradiation. This drop was most likely caused by thee introduction of deep nonradiative recombination centers within the bandgap. Room temperature aging for 48 hours led to band-to-band PL intensity partial recovery, while annealing at 473K caused an almost complete recovery.
