Ab initio-based approach to elemental growth process on the InAs wetting layer grown on GaAs substrate

The surface reconstructions and migration behavior on InAs(001) and InAs(111)A wetting layer on GaAs substrate are systematically investigated by our ab initio-based approach and Monte Carlo simulations. The ab initio-based approach incorporates the chemical potentials of In atom and As4 molecule in the gas phase as functions of temperature T   and beam equivalent pressure pAs4pAs4. The calculated surface phase diagrams imply that the respective stable surface structures of InAs(001) and InAs(111)A are the (2×4)α2 and the In-vacancy surfaces at conventional growth conditions at T∼700–750 K and pAs4pAs4∼10−7–10−6 Torr. On these surfaces, adsorption–desorption boundary for In atom appears below the growth temperatures. Therefore, In adatoms tend to desorb from the InAs(001) and the InAs(111)A surfaces at equilibrium. Kinetic behavior of In adatoms obtained by the Monte Carlo simulations reveal that life time τ and diffusion length L of In adatoms are small such as τ=1.59×10−3 s and L=618 nm on the InAs(001) and τ=4.35×10−14 s and L=0.204 nm on the InAs(111)A. On the basis of these results, the growth process on the InAs(111)A is discussed in terms of self-surfactant effect where simultaneous As adsorption makes In atom adsorb on the surface.

► Ab initio-based approach is applied to InAs wetting layer surfaces at growth conditions.
► Stable InAs wetting layer surfaces are the (001)–(2×4)α2 and the (111)-In-vacancy surfaces.
► In adatoms tend to desorb from the InAs wetting layer surfaces at equilibrium.
► In adatom kinetics are investigated using Monte Carlo method on the InAs wetting layer surfaces.
► The growth process on the InAs(111)A wetting layer is discussed in terms of self-surfactant.