Influence of indium on the vibrational modes of dilute narrow band gap GaNAs alloys

To understand the influence of indium on the localized vibrational modes (LVMs) in dilute GaN_xAs_1-x alloys we have analyzed the infrared absorption and Raman scattering data using a realistic lattice dynamical theory in the Greens function framework. The incorporation of In into GaN_xAs_1-x affected the local bonding of N-atom through alteration of strain distributions. By including the force variations in In-N and Ga-N bonds and analyzing the experimental data in dilute Ga_1-yIn_yN_xAs_1-x alloys with x≤ 0.04 and y≤ 0.12 we are able to identify three N-centred clusters.