Interdependence of strain and shape in self-assembled coherent InAs islands on GaAs

Abstract
Self-assembled coherent InAs islands on GaAs (100) have been investigated by a novel version of grazing-incidence diffraction ("iso-strain scattering"). This method permits the determination of the interdependence of strain and shape, as well as the relaxation gradient within the InAs dots. The relaxation in the islands ranges from fully strained at the bottom to completely relaxed at the top of the islands. The radius of the dots at a given height depends linearly on the local elastic lattice relaxation, with a rapidly increasing relaxation gradient when approaching the top of the islands.