Nucleation of misfit dislocations in strained-layer InGaAs on GaAs

Abstract Misfit dislocations at the interface of a thin epitaxial layer of In0-18Ga0-82As on GaAs have been studied by glancing incidence double-crystal synchrotron X-ray topography. The misfit dislocation density increases dramatically as the layer thickness increases from 17 to 18nm across the sample. Clear evidence for the nucleation of misfit dislocations at threading dislocations from the substrate is presented.