Local vibrational mode absorption of nitrogen in GaAsN and InGaAsN layers grown by molecular beam epitaxy

The nitrogen-related infrared absorption band at 471cm (1) is found in the ternary and qunternary alloys GaAs1-xNx and InyGa1-yAs1-xNx, respectively, grown by solid-source molecular beam epitaxy. Implantation experiments with the isotopes N-14 and N-15 show that the band is due to a local vibrationa l mode of isolated nitrogen on the arsenic site. The strength of the band i n GaAs1-xNx layers correlates for x <0.01 quantitatively with the decrease of the lattice parameter determined by X-ray diffraction. We conclude furth er that nitrogen in In Ga1-yAs1-xNx quantum well structures is surrounded b y four nearest-neighbor gallium atoms. (C) 2001 Elsevier Science B.V. All r ights reserved.