Formation of strain-induced Si-rich and Ge-rich nanowires at misfit dislocations in SiGe: A model supported by photoluminescence data

Molecular dynamics simulations with the Tersoff potential of the strain distribution around 60° misfit dislocation in a heteroepitaxial SiGe film confirm that highly compressed and expanded, cylindrical nanometer-sized regions appear on opposite sides of the (111) glide plane. Such a configuration is suggested to generate opposite chemical potential gradients for Si and Ge diffusion and, as verified by a Monte Carlo simulation, in the formation of Si-rich and Ge-rich nanowires along the dislocation core. This model is supported by photoluminescence measurements as a function of annealing temperature and time.