Thick cubic GaN film growth using ultra-thin low-temperature buffer layer by RF-MBE

1.8 μm thick high-quality cubic GaN film was successfully grown on GaAs (1 0 0) using an ultra-thin, low-temperature GaN buffer layer by a plasma-assisted molecular beam epitaxy. The 'as-grown' low-temperature buffer layer was amorphous and ultra-thin (∼6 Å), which is a necessity condition to grow a pure cubic GaN epilayer. FWHM of X-ray rocking curve (c-GaN (2 0 0) diffraction) is as narrow as 28.7 arcmin.