ABSTRACT

We study the crystal quality of cubic GaN grown on GaAs by plasma-assisted molecular beam epitaxy and its dependence on the growth conditions. Even if epitaxial growth is established, the resulting layer may include significant volume fractions of the hexagonal phase. We find that the major parameter controlling the phase purity of cubic GaN films is the surface stoichiometry during growth. We present a method which allows the real-time monitoring of the surface stoichiometry and which thus enables us to achieve single-phase cubic GaN films.