Surface reconstructions of zinc-blende GaN/GaAs(001) in plasma-assisted molecular-beam epitaxy

We identify the growth conditions required for the synthesis of purely cubic GaN films on GaAs(001) by means of plasma-assisted molecular-beam epitaxy. It is shown that it is the surface stoichiometry which governs the phase composition and which thus has to be tightly controlled in order to avoid nucleation of hexagonal grains. Such control over the surface stoichiometry is achieved by investigating the surface reconstructions of zinc-blende GaN under both static and dynamic conditions by in situ reflection high-energy electron diffraction.