By using ab initio calculations, the paths and activation energies were determined for the diffusion of group-IV atoms (Si, Ge, Sn) on top of the As layer on As-passivated Si(111), and for exchange with an As atom. The kinetics of Si, Ge and Sn adatoms were substantially different: Si adatoms were readily incorporated under the As layer. Ge adatoms diffused far on top of the As layer and could reach existing steps. It was shown, for the first time, that the ratio between diffusion and exchange barriers depended strongly upon the strain of the growing Ge film. The Sn atoms remained on top of the As layer.

Surfactant Mediated Heteroepitaxy versus Homoepitaxy - Kinetics for Group-IV Adatoms on As-Passivated Si(111) and Ge(111). K.Schroeder, A.Antons, R.Berger, S.Blügel: Physical Review Letters, 2002, 88[4], 046101 (4pp)