Effects of electron irradiation on photoluminescence from 1-eV GaInNAs epilayers subject to thermal annealing

We have investigated the influence of 7-MeV electron irradiation to the dose of 1.8×10¹⁶ cm^-2 and subsequent rapid thermal annealing on luminescence performance of lattice-matched 1-eV GaInNAs-on-GaAs epilayers, grown by molecular beam epitaxy. The study has been done by means of 9-K photoluminescence (PL) in conjunction with 300-K photoreflectance (PR) spectroscopy and x-ray diffraction measurements. A drastic deterioration in PL has been seen upon the electron irradiation. When rapid thermally annealed at 800 ^oC for 1 min an enhancement in PL has been observed as compared to the reference non-irradiated sample. The irradiation-promoted enhancement in PL upon annealing has been accompanied by a small additional blue shift (BS) of the PL. This additional annealing-induced BS has been found to be mainly due to an irradiation-promoted enhancement in In-N bonds formation.