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 scattering 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, and a density of states spectrum, which is in accord with neutron scattering measurements.Our results for amorphous GaN show that the vibrational properties of a-GaN may be attributed to the nearly crystalline nearest-neighbor geometry of the amorphous network.