A geometrical model for the description of the AlN shell morphology in GaN-AlN core-shell nanowires

摘要

A geometrical model based on the one formulated by Foxon et al. [J. Cryst. Growth 311, 3423 (2009)] is developed to describe the morphology of AlN shells in GaN-AlN core-shell nanowires grown by plasma-assisted molecular beam epitaxy. The shell aspect ratio is studied as a function of the atomic beam flux incidence angles and of the ratio between Al and N species. The comparison between experimental data and the developed geometrical model suggests the diffusion of about 55% of Al atoms from the side walls to the top surface.