Two-dimensional lattice-mismatched heteroepitaxy of germanium on silicon beyond the critical thickness by introducing a surfactant

Abstract
Smooth germanium films have been grown on Si(100) surfaces in a two-dimensional fashion by using antimony as a surfactant. Different ways of depositing the surfactant (at the interface between substrate and growing film, after the deposition of a thin Ge layer, and by coevaporation) have been investigated. The grown films, investigated by high-resolution electron microscopy and reflection high-energy electron diffraction, show that the surfactant does not act at the interface. A kinetical approach for the description of surfactant behavior in the growing front is necessary.