Analysis of the dislocation structure at the Ge/Si(111) heterointerface

Abstract

We demonstrate the formation of a modified triangular network of Shockley edge partial misfit dislocations at a plastic-relaxation level of ρ = 0.72 of 3D Ge(111) islands grown on a wetting layer. The network forms due to the offset of one dislocation family by 40% of the interdislocation spacing. We report ultra-high-vacuum scanning tunnel microscopy and high-resolution transmission electron microscopy data and the results of theoretical calculation of the stress fields induced in the film volume by the introduction of misfit dislocations. We establish the Ge-film-thickness range acceptable for observing elastic undulation of the surface by scanning tunneling microscopy.