Journal of Crystal Growth, Vol.477, 239-242, 2017
Self-assembly of vertically aligned quantum ring-dot structure by Multiple Droplet Epitaxy
We successfully grow vertically aligned quantum ring-dot structures by Multiple Droplet Epitaxy technique. The growth is achieved by depositing GaAs quantum rings in a first droplet epitaxy process which are subsequently covered by a thin AlGaAs barrier. In a second droplet epitaxy process, Ga droplets preferentially position in the center indentation of the ring as well as attached to the edge of the ring in [1 (1) over bar0] direction. By designing the ring geometry, full selectivity for the center position of the ring is achieved where we crystallize the droplets into quantum dots. The geometry of the ring and dot as well as barrier layer can be controlled in separate growth steps. This technique offers great potential for creating complex quantum molecules for novel quantum information technologies. (C) 2017 Published by Elsevier B.V.
Keywords:Molecular beam epitaxy;Selective epitaxy;Semiconducting gallium arsenide;Low dimensional structures