On the luminescence and structural properties of GaInNAs lattice matched to GaAs

We have investigated the luminescence and structural properties of as-grown and thermally annealed lattice-matched GaInNAs-on-GaAs epilayer, grown by molecular-beam epitaxy. The study has been done by means of photoluminescence (PL) in conjunction with Raman spectroscopy and X-ray diffraction measurements. We have found that besides the near band-edge PL emission a broad emission band can be seen in longer wavelengths in 9-K PL. The broad PL band is related to presence of nitrogen into lattice likely involving a N-related defect Raman spectroscopy showed that nitrogen appears to be mainly located on substitutional sites in "short-range-order clusters" as N-Ga₄ and to a lesser extent as N-Ga₃In clusters". There were also been indications of presence of off-substitutional nitrogen. Post-growth thermal annealing has been seen to remarkably enhance and to blue shift the near band-edge PL. At the same time the broad PL band has only slightly decreased without any spectral shift. The blue is mainly due to formation of In-N bonds. Electron irradiation applied prior to annealing has promoted a further enhancement in the near-band edge PL and substantially decreased the broad PL band