Nonradiative-recombination-enhanced defect-structure transformation in low-temperatureγ-ray-irradiated InP

Low-temperature $\gamma$-ray irradiation and subsequent minority-carrier injection are found to enhance a defect-structure transformation from a major irradiation-induced deep hole trap ($E_v+0.32\mathrm{}$eV) to a deeper hole-trap center ($E_v+0.52\mathrm{}$eV) in $p$-type InP. Direct experimental evidence is shown to demonstrate the role of the 0.32-eV level as an efficient nonradiative recombination center which competes with other radiative transition channels. The results show a recombination-enhanced reaction mechanism at the anion-displacement center with strong electron-phonon couplings.