Resonant Raman study of local vibration modes in AlGaAsN layers

We report on resonant inelastic light scattering in dilute AlGaAsN films. Intense narrow peaks associated to N-related local vibration modes (LVM) have been observed around 325, 385, 400, 450, 500 and 540 cm−1. Their frequencies are compared to density functional theory supercell calculations of AlnGa4−nN complexes (n=1−4). We find clear indications of the formation of Al4N complexes. The values of the extended phonon frequencies reveal changes in the N distribution depending on the growth conditions. The LVM spectra are resonant in the energy range from 1.75 to 1.79 eV, which corresponds to an N-related electronic transition. Our results confirm the preferential bonding of N to Al in AlGaAsN.