Island Nucleation and Growth on Reconstructed GaAs(001) Surfaces

Abstract

The initial stages of homoepitaxy on GaAs(001) are studied with atomic-resolution scanning tunneling microscopy and Monte Carlo simulations that include the zinc blende structure of GaAs, the ( $2\ifmmode\times\else\texttimes\fi{}4$) reconstruction of the (001) surface, and the kinetics of ${\mathrm{As}}_{2}$ incorporation. The reconstruction is found to favor nucleation on the top-layer arsenic dimers and to cause small islands to be unstable until they adopt the local ( $2\ifmmode\times\else\texttimes\fi{}4$) structure.