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

Abstract

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 grown on GaAs (001) substrates by metalorganic chemical vapor deposition (MOCVD). High temperature annealing is employed to treat the as-grown c-GaN thin films. The characterization of the c-GaN films is investigated by photoluminescence (PL) and Raman scattering spectroscopy. The change conditions of the hexagonal phase content in the metastable c-GaN are reported. There is a boundary layer existing in the c-GaN/GaAs film. When being annealed at high temperature, the intensity of the T0B and LOB phonon modes from the boundary layer weakens while that of the E2 phonon mode from the hexagonal phase increases. The content change of hexagonal phase has closer relationship with annealing temperature than with annealing time period.