In rich In1−x Ga x N: Composition dependence of longitudinal optical phonon energy

The composition dependence of longitudinal optical (LO) phonon energies in undoped and Mg-doped In1−xGaxN samples are determined using Raman spectroscopy in the range of Ga fraction from x = 0 to x = 56%. The LO phonon energy varies from 73 meV for InN to 83 meV for In1−xGaxN with 56% Ga. Independent measurements of temperature dependent mobility at high temperatures where LO phonon scattering dominates the transport were also used to obtain the LO phonon energy for x = 0 and x = 20%. The results obtained from the two independent techniques compare extremely well.