ISLAND NUCLEATION AND GROWTH ON RECONSTRUCTED GAAS(001) SURFACES

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 3 4) reconstruction of the (001) surface, and the kinetics of 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 3 4) structure. [S0031-9007(98)06564-8]