The evolution of InAs quantum dot (QD) formation is studied on GaAs ring-like nanostructures fabricated by droplet homo-epitaxy. This growth mode, exclusively performed by a hybrid approach of droplet homo-epitaxy and Stransky-Krastanor (S-K) based QD self-assembly, enables one to form new QD morphologies that may find use in optoelectronic applications. Increased deposition of InAs on the GaAs ring first produced a QD in the hole followed by QDs around the GaAs ring and on the GaAs (100) surface. This behavior indicates that the QDs prefer to nucleate at locations of high monolayer (ML) step density.
KeywordsGaAs/GaAs droplet homo-epitaxy InAs quantum dots Molecular beam epitaxy Self-assembly
The authors thank Dr. John Shultz for his strong support in the facility maintenance and the financial support of the NSF (through Grant DMR-0520550). The WSxM© image processing program was used in this paper (http://www.nanotec.es).