Transformation kinetics of homoepitaxial islands on GaAs(001)

Kinetic Monte Carlo simulations, in situ scanning tunneling microscopy, and mean-field rate equations are used to characterize the atomistic nucleation, growth, and structural transformation kinetics of homoepitaxial islands on GaAs(001)-(2×4). After an induction period, islands are formed that do not adopt the reconstruction of the substrate, but transform into β2(2×4) structures as they grow. Comparison of measured and simulated island statistics at several coverages reveals that the unreconstructed islands initially grow slowly in size and rapidly in number, whereas the transformed islands have an appreciably higher growth rate but appear much more gradually.