Evolution of InGaN/GaN nanostructures and wetting layers during annealing

Abstract

InGaN nanostructures grown by metal-organic vapour phase epitaxy were annealed in NH₃ for varying lengths of time. In the early stages of the anneal, the nanostructure number density is stable, but an unusual phenomenon is observed whereby previously randomly distributed nanostructures form small clusters. At longer anneal times, the epilayer starts to decompose and the nanostructure density decreases simultaneously, but the clustering persists even for rather low nanostructure densities. Cluster formation may be due to the thermodynamics of nanostructure growth on an undulating substrate surface.