Raman tensor of AlN bulk single crystal

Abstract

The angle dependence of optical phonon modes of an AlN bulk single crystal from the m-plane (1100) and c-plane (0001) surfaces, respectively, is investigated by polarized Raman spectroscopy in a backscattering configuration at room temperature. Corresponding Raman selection rules are derived according to measured scattering geometries to illustrate the angle dependence. The angle-dependent intensities of phonon modes are discussed and compared to theoretical scattering intensities, yielding the Raman tensor elements of A1(TO), E22, E1(TO), and A1(LO) phonon modes and the relative phase difference between the two complex elements of A1(TO). Furthermore, the Raman tensor of wurtzite AlN is compared with that of wurtzite ZnO reported in previous work, revealing the intrinsic differences of lattice vibration dynamics between AlN and ZnO.