Raman scattering study on anisotropic property of wurtzite GaN

The phonon anisotropy property of the GaN wurtzite crystal is studied using angular dependent Raman spectroscopy both theoretically and experimentally. The polarized Raman scattering spectra were recorded from the cross section of c-axis oriented GaN films as a function of the angle between the incident laser polarization direction and the film normal direction in three different configurations. The Raman intensity of A1(TO) showed a sinusoidal dependence on the rotating angle, as also did the E1(TO) mode, while the E2 mode has a quite different behavior. The theoretical analysis takes into account the susceptibility contribution and the phase differential of different vibrating elements.