Deformation potentials of the E2(high) phonon mode of AlN

AlN layers grown on (111)-oriented silicon substrates were studied by Raman spectroscopy. The deformation potentials of the nonpolar E-2(high) phonon mode of hexagonal AlN were derived from phonon frequency shifts under biaxial stress applied to the layer. Stress was applied by mechanical bending of the wafer with resulting in-plane biaxial stress in AlN. The technique allows one to avoid the uncertainty of x-ray diffraction strain determination inherent to experimental methods commonly used for deformation potentials determination in III-V nitrides. The obtained values for the phonon deformation potentials are in reasonably good agreement with previous theoretical calculations. For pure biaxial stress, we determine a phonon frequency shift of 3 cm(-1)/GPa. (C) 2002 American Institute of Physics.