Role of Noise in Nanostructure Formation: A Theoretical Investigation of Quantum Dots and Quantum Dot Molecules

TL;DR

This paper presents a theoretical model explaining how noise influences the formation of quantum dots and quantum dot molecules during silicon germanium heteroepitaxy, revealing dual roles of noise in promoting or inhibiting nanostructure growth.

Contribution

It introduces a continuum theory incorporating noise effects to explain the transition between quantum dot and molecule formation in epitaxial growth.

Findings

Changing flux induces QD to QDM transition.

Noise promotes QDM formation via pit nucleation.

Stochastic effects can inhibit QDM formation.

Abstract

We theoretically model the formation of quantum dots(QDs) and quantum dot molecules(QDMs) in silicon germanium heteroepitaxy by explicitly incorporating the role of noise in a continuum theory for surface evolution in molecular beam epitaxy. Using the connection between flux and noise, we explain how changing flux can lead to a transition from QD to QDM formation, as seen in experiments. In these systems we show a dual role of noise in nanostructure growth; one where it promotes formation of QDMs via pit nucleation, and another where it curtails QDM formation due to stochastic effects.