First-Principle Calculation of Migration Processes of As during Growth on GaAs(001)

Abstract

The microscopic migration of an As adatom on a Ga-terminated GaAs(001) surface is investigated by performing first-principle calculations using density functional theory and a slab model of the surface, because the importance of As adatom migration has been reported. The obtained values of barrier energy are compared with those to hopping in the kinetic Monte Carlo simulation. The anisotropic migration of the As adatom is clarified, which agrees with the result of the kinetic Monte Carlo simulation as well as the properties obtained by the scanning tunneling microscopy observation. It is shown that an As adatom is more mobile than a Ga adatom, and the kinetics of both As and Ga atoms on the growing surface are important during molecular beam epitaxial growth.