Raman phonon modes of zinc blende InxGa1−xN alloy epitaxial layers

Transverse-optical (TO) and longitudinal-optical (LO) phonons of zinc blende ${\mathrm{In}}_x{\mathrm{Ga}}_{\text{1−x}}\mathrm{N}$ $\text{(0⩽x⩽0.31)}$ layers are observed through first-order micro-Raman scattering experiments. The samples are grown by molecular-beam epitaxy on GaAs (001) substrates, and x-ray diffraction measurements are performed to determine the epilayer alloy composition. Both the TO and LO phonons exhibit a one-mode-type behavior, and their frequencies display a linear dependence on the composition. The Raman data reported here are used to predict the $A_1$ (TO) and $E_1$ (TO) phonon frequencies of the hexagonal ${\mathrm{In}}_x{\mathrm{Ga}}_{\text{1−x}}\mathrm{N}$ alloy.