Raman scattering by surface polaritons in cubic GaN epitaxial layers

Abstract We present the results of Raman experiments on cubic GaN epitaxial layers grown on (0 0 1) GaAs substrates. A distinct line observed at the low-frequency edge of the LO phonon in the backscattering spectra is shown to be due to the upper surface polariton mode. We show that the high transparency of the layer results in a weak efficiency of scattering by the lower polariton mode and strong increase of the scattering in backward configuration. The research reveals a high sensitivity of the surface polariton mode to the film thickness, doping level and quality of the GaN GaAs interface.