Epitaxial growth of cubic and hexagonal GaN on GaAs by gas-source molecular-beam epitaxy

Abstract

GaN epilayers were grown on GaAs substrates by gas-source molecular-beam-epitaxy technique using dimethylhydrazine as a nitrogen source. It was found that cubic GaN grows on GaAs (001) surfaces epitaxially, while hexagonal GaN grows on GaAs (111) surfaces, from the analyses of x-ray diffraction and reflection high-energy electron diffraction patterns. Cathodoluminescence measurements suggested that the band-gap energy of cubic GaN is around 0.37 eV larger than that of hexagonal GaN.