Structural order in oxygenated gallium nitride films

Structural order in nanocrystalline, oxygenated GaN thin films (thickness ~ 500 nm) has been examined. The films were grown using low-pressure chemical vapor deposition of (CHâ‚Æ')â‚‚GaNâ‚Æ' single source precursor. During deposition, residual oxygen from the vacuum environment was incorporated into the films. Photoemission spectroscopy indicated that oxygen mainly substituted nitrogen during deposition. Long-range X-ray diffraction indicated that the films were oriented along the hexagonal (002) direction when the incorporated concentration of oxygen was lower than 25 atomic % (at. %). Above this, the films were amorphous. The results of angle-dependent near-edge X-ray absorption fine structure facilitated the formation of a short-range structural model, which explained the influences of the oxygen concentration on the long-range order in the films. These studies are useful in understanding the structural evolution in doped-nitride films.