Molecular Dynamics Study of Coherent Island Energetics, Stresses, and Strains in Highly Strained Epitaxy

Abstract

The behavior of energetics, atomically resolved stress, and strain in coherent three-dimensional islands observed in highly strained semiconductor heteroepitaxy is examined for the first time via a molecular dynamics study of a model Ge/Si system. Evidence is found for the common but hitherto unsubstantiated practice of representing the island energy as a sum of surfacelike and bulklike terms, down to rather small islands, but with significantly renormalized coefficients indicating marked modifications of the surface and volume elastic energies commonly employed in continuum descriptions.