Raman scattering studies on single-crystalline bulk AlN under high pressures

We report on the Raman analysis of wurtzite single-crystalline bulk AlN under hydrostatic pressures up to 10 GPa. The pressure dependence of the AlN phonon frequencies was investigated. Mode Gruneisen parameters of 1.39, 1.57, 1.71, 0.93, and 1.26 were determined for the A(1) (TO), E-1 (TO), E-2 (high), A(1) (LO), and the quasi-longitudinal optical phonons, respectively. Recent theoretical calculations underestimate the pressure-induced frequency shift of the AlN phonons by about 20%-30%. Mode Gruneisen parameters of AlN were compared to those of GaN. (C) 2001 American Institute of Physics.