Monodisperse (In, Ga)N insertions in catalyst-free-grown GaN(0001) nanowires

Abstract

Vertical stacks of (In, Ga)N insertions in GaN nanowires are grown by molecular beamepitaxy. The chemical composition and strain within the structure are probed by acombination of high-resolution x-ray diffraction, transmission electron microscopy, andgeometrical phase analysis. The (In, Ga)N insertions are coherently strained.Finite-element simulations strongly support an effective strain relaxation mechanism of thesurrounding GaN matrix due to the nanowire geometry, leading to high-quality (In,Ga)N/GaN nanowire heterostructures. An intense green photoluminescence emission isobserved and attributed to an inter-well transition between the stacked (In, Ga)Ninsertions.