Ion-assisted deposition of amorphous GaN: Raman and optical properties

We report the preparation of amorphous GaN by ion-assisted deposition and s tudies of the Raman and optical response of the resulting films. The films are transparent across the visible and show an edge whose energy and struct ure are in close agreement with crystalline material, suggesting a low dens ity of gap states and homopolar bonds. The Raman spectrum is similar to a b roadened vibrational density of modes calculated for wurtzite GaN, with a R aman cross section which varies among the vibrational bands. (C) 2001 Ameri can Institute of Physics.