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 nucleatio n, growth, and structural transformation kinetics of homoepitaxial islands on GaAs(001)-(2 x 4). After an induction period, islands are formed that do not adopt the reconstruction of the substrate, but transform into beta2(2 x 4) structures as they grow. Comparison of measured and simulated island s tatistics at several coverages reveals that the unreconstructed islands ini tially grow slowly in size and rapidly in number, whereas the transformed i slands have an appreciably higher growth rate but appear much more graduall y. (C) 2000 Elsevier Science B.V. All rights reserved.