Journal of Crystal Growth | 2021
Effect of surface structural change on adsorption behavior on InAs wetting layer surface grown on GaAs(001) substrate
Abstract
Abstract The effect of surface structural change on the adsorption behavior of In adatom during the growth of InAs wetting layer (WL) on GaAs(001) substrate is theoretically investigated on the basis of ab initio calculations and Monte Carlo (MC) simulations. The ab initio calculations for InAs WL surface on GaAs(001) substrate reveal that the adsorption of In adatom is promoted on the (4 × 7) surface, which corresponds to the boundary between the (2 × 4) and (4 × 3) surfaces. The promotion of In adsorption on the (4 × 7) surface is due to the relaxation of atoms located near the In adatom. Furthermore, the MC simulations using the calculated total energies of various surface structures obtained by ab initio calculations demonstrate that the number of stable adsorption sites of In adatom becomes the largest around θ =1.1 monolayer (ML). This is because the area of the (4 × 7) surface with many stable adsorption sites increases with InAs coverage for 0.9 ⩽ θ ⩽ 1.15 ML. The calculated results manifest that the boundary between (2 × 4) and (4 × 3) surfaces is crucial for the nucleation and growth on InAs WL surface grown on the GaAs(001) substrate.