Vibrational properties of amorphous GaN

The vibrational densities-of-states (DOS) of crystalline hexagonal GaN and a simulated amorphous GaN (a-GaN) structure are calculated. Neutron scatter ing spectra of simulated amorphous GaN structures are also calculated. Our results for hexagonal GaN yield energies of zone-centered phonons which are consistent with experimental Raman and infrared (IR) absorption studies, a nd a density of states spectrum, which is in accord with neutron scattering measurements. Our results for amorphous GaN show that the vibrational prop erties of a-GaN may be attributed to the nearly crystalline nearest-neighbo r geometry of the amorphous network. (C) 2001 Elsevier Science B.V. All rig hts reserved.