Photoluminescence characterization of GaN thin film grown by atmospheric pressure organometallic vapor phase epitaxy

Thin films of gallium nitride (GaN) were successfully prepared by our atmospheric pressure (AP) organometallic vapor phase epitaxy (OMVPE) system using GaN buffer layer over basal plane (0001) sapphire substrates. In the present study, strong band-edge photoluminescence (PL) in GaN films is observed. The variations of the growth temperature and ammonia/trimethylgallium (NH3/TMG) mass flow ratio with the full width at half maximum (FWHM) of band-edge luminescence (IBE, respectively, indicate that we could obtain ranges of the growth temperature and the NH3/TMG ratio to have high quality GaN single crystal. The band-edge to deep-level luminescence (IDL) ratio (IBE/IDL) also reveals that we could obtain optimized appropriate growth temperature and the supply of active nitrogen of excellent optical properties.