Influence of electron irradiation and rapid thermal annealing on photoluminescence from GaAsNBi alloys

We have examined the influence of electron irradiation and rapid thermal annealing on photoluminescence emission from GaAsNBi alloys. Electron irradiation of a 1-eV compressively strained GaNAsBi-on-GaAs epilayer, grown by molecular beam epitaxy and subsequently rapidly thermally annealed, is found to induce much stronger photoluminescence than what is observed for an identical as-grown sample upon annealing. At the same time, annealing of the irradiated sample caused a negligible spectral blueshift and reduced alloy potential energy fluctuations. These irradiation-related phenomena occurred without a change in the alloy macroscopic composition as revealed by x-ray diffraction and are mainly related to the nitrogen incorporated into non-substitutional sites in the quaternary alloy.