Three-dimensional geometry of nanometer-scale AIN pits: A new template for quantum dots?

Abstract

A new method to determine the exact three-dimensional (3D) geometry of aluminum nitride (AlN) nano-pits and their use as a template for epitaxially growing quantum dots (QDs) have been demonstrated. Z-contrast imaging that is relatively insensitive to focus conditions and specimen thickness than phase-contrast high resolution transmission electron microscopy was used to determine the 3D geometry of AlN pits. AlN could easily be distinguished from GaN and sapphire from the Z-contrast of a Z-contrast image, even without additional chemical analysis. It was observed that the pits impact the growth mechanism of the subsequently grown layer and its quality. It was also reported that the mass transport on the basis of AlN pits led to the bending of threading dislocations. These AlN nano-pits can be a promising template on which, III-nitride based quantum dots can be formed.