Reaction-limited island nucleation in molecular beam epitaxy of compound semiconductors.

Kinetic Monte Carlo simulations on the basis of rates derived from density-functional calculations are used to investigate the atomic processes in molecular beam epitaxy of GaAs. This approach puts us in a position to describe island nucleation and growth in all relevant atomistic detail by bridging the gap in length and time scales between the mesoscopic scale of growth morphology and the atomic scale. We observe a nonmonotonic dependence of the island density on growth temperature related to a reversible surface reaction of As2 with Ga adatoms.