Fabrication of 10-Nanometer-scale GaAs Dot Structures by In Situ Selective Gas Etching with Self-Assembled InAs Dots as a Mask

We report on a novel method of fabricating 10-nm-scale GaAs dot structures using molecular beam epitaxy and in situ gas etching. Self-assembled nanometer-scale InAs dots are formed first and are used as masks for the subsequent etching of GaAs by Cl 2 gas. In this approach, we also make use of HCl gas etching to remove selectively the InAs wetting layer as well as the InAs dots to yield clean and strain-free GaAs dot structures. The height and base diameter of resultant GaAs dots are studied by atomic force microscopy and found to be 10±2 nm and 30±5 nm, respectively.