SURFACE RECONSTRUCTIONS OF ZINCBLENDE 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-be am epitaxy. It is shown that it is the surface stoichiometry which gov erns the phase composition and which thus has to be tightly controlled in order to avoid nucleation of hexagonal grains. Such control over t he surface stoichiometry is achieved by investigating the surface reco nstructions of zinc-blende GaN under both static and dynamic condition s by in situ reflection high-energy electron diffraction.