InP ring-like nanostructures on In0.49Ga0.51P grown by droplet epitaxy

We have successfully to fabricate self-assembled InP ring-like nanostructures on lattice-matched In0.49Ga0.51P 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 P, 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 indiurn thickness is thicker than 1.6 ML. The ring-like nanostructure is formed when indium deposition at 120 degrees C and the ring shape and the ring-like quantum-dot molecule is formed when indium deposition at 150 degrees C 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.