Ultra-Thin Epitaxial Structures: The Ge/Si System

Epitaxial growth of ordered, single-crystalline superlattices is often limited by the lattice mismatch between the constituent elements or alloys. If the difference in the lattice parameter is large, as is the case in Si-Ge system (4.2%), the critical layer thickness hc for epitaxial growth of one element on top of the other becomes very small and difficult to measure.