Strain effect on adatom binding and diffusion in homo- and heteroepitaxies ofSiandGeon(001)Surfaces

Abstract

Strain dependence of adatom binding energies and diffusion barriers in homo- and heteroepitaxies of Si and Ge on s001d surface has been studied using first-principles calculations. In general, Si adatom binding energies and diffusion barriers are larger on Sis001d and Ges001d surfaces than a Ge adatom, in accordance with decreasing bond strength from Si-Si to Si-Ge and to a Ge-Ge bond. The overall surface diffusion anisotropy of Si and Ge adatoms is found to be comparable on both Sis001d and Ges001d. The essentially linear dependence of binding energies and diffusion barriers on external strain is reproduced in all the cases, giving strong evidence for a priori quantitative prediction of the effect of external strain on adatom binding and surface diffusion.