Annealing behavior of hexagonal phase content in cubic GaN thin films grown on GaAs (001) by MOCVD

The annealing behavior of the hexagonal phase content in cubic GaN (c-GaN) thin films grown on GaAs (001) by MOCVD is reported. C-GaN thin films are g rown on GaAs (001) substrates by metalorganic chemical vapor deposition (MO CVD). High temperature annealing is employed to treat the as-grown c-GaN th in films. The characterization of the c-GaN films is investigated by photol uminescence (PL) and Raman scattering spectroscopy. The change conditions o f the hexagonal phase content in the metastable c-GaN are reported. There i s a boundary layer existing in the c-GaN/GaAs film. When being annealed at high temperature, the intensity of the TOB and LOB phonon modes from the bo undary layer weakens while that of the E-2 phonon mode from the hexagonal p hase increases. The content change of hexagonal phase has closer relationsh ip with annealing temperature than with annealing time period.