InP Ring-like Nanostructures on Ino.49Gao.51P Grown by Droplet Epitaxy

The authors have successfully fabricated self-assembled InP ring-like nanostructures on lattice-matched In_0.49 Ga_0.51P on GaAs substrates by solid-source molecular-beam epitaxy using droplet epitaxy technique. The growth sequence is initiated by indium deposition which was intended to form indium droplets and followed by exposure P₂ beam to crystallize the indium droplets to InP. Dependence of the surface morphology on the indium thickness and substrate temperature was investigated. It is observed that the ring-shape nanostructure is formed when indium thickness is 1.6 ML and the ring shape and the ring-like quantum-dot molecule is formed when the indium thickness is thicker than 1.6 ML. The ring-like nanostructure is formed when indium deposition at 120degC and the ring shape and the ring-like quantum-dot molecule is formed when indium deposition at 150degC or higher. The density, height and number of dot per molecule of ring-shape nanostructure also depended on the indium thickness and on the substrate temperature while indium deposition.