Anisotropy and Order of Epitaxial Self-Assembled Quantum Dots

TL;DR

This paper investigates how crystal anisotropy influences the order of self-assembled quantum dots during early formation stages, highlighting the importance of elastic anisotropy and wetting potential effects.

Contribution

It introduces a linear analysis of surface evolution models to elucidate the role of anisotropy and wetting potential in promoting quantum dot order.

Findings

Two relevant correlation lengths identified, one linked to crystal anisotropy.

SAQD order is enhanced near the critical surface height for 3D growth.

Elastic anisotropy crucially affects SAQD ordering.

Abstract

Epitaxial self-assembled quantum dots (SAQDs) represent an important step in the advancement of semiconductor fabrication at the nanoscale that will allow breakthroughs in electronics and optoelectronics. In these applications, order is a key factor. Here, the role of crystal anisotropy in promoting order during early stages of SAQD formation is studied through a linear analysis of a commonly used surface evolution model. Elastic anisotropy is used a specific example. It is found that there are two relevant and predictable correlation lengths. One of them is related to crystal anisotropy and is crucial for determining SAQD order. Furthermore, if a wetting potential is included in the model, it is found that SAQD order is enhanced when the deposited film is allowed to evolve at heights near the critical surface height for three-dimensional film growth.