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

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.