Structure and composition of non-polar (11-20) InGaN nanorings grown by modified droplet epitaxy

Abstract

Droplets grown by modified droplet epitaxy on non-polar (11-20) surfaces of InGaN epilayers on GaN have been seen to be associated with underlying ring-like structures. This work discusses droplet etching as a possible mechanism for ring formation, and droplet creeping as a possible explanation for the droplets sitting askew of the ring centre. Transmission electron microscopy (TEM) analysis shows the droplets to move along the 〈0001〉 c-axis, and indicates that they have a very high indium content. The image shows atomic force microscopy (AFM) data of a double-ring structure, rendered in 3D.