Beyond the heteroepitaxial quantum dot: Self-assembling complex nanostructures controlled by strain and growth kinetics

J. L. Gray, R. Hull, Chi Hang Lam, P. Sutter, J. Means, J. A. Floro

Research output: Journal article publicationJournal articleAcademic researchpeer-review

47 Citations (Scopus)

Abstract

Heteroepitaxial growth of GeSi alloys on Si (001) under deposition conditions that partially limit surface mobility leads to an unusual form of strain-induced surface morphological evolution. We discuss a kinetic growth regime wherein pits form in a thick metastable wetting layer and, with additional deposition, evolve to a quantum dot molecule-a symmetric assembly of four quantum dots bound by the central pit. We discuss the size selection and scaling of quantum dot molecules. We then examine the key mechanism-preferred pit formation-in detail, using ex situ atomic force microscopy, in situ scanning tunneling microscopy, and kinetic Monte Carlo simulations. A picture emerges wherein localized pits appear to arise from a damped instability. When pits are annealed, they extend into an array of highly anisotropic surface grooves via a one-dimensional growth instability. Subsequent deposition on this grooved film results in a fascinating structure where compact quantum dots and molecules, as well as highly ramified quantum wires, are all simultaneously self-assembled.
Original languageEnglish
Article number155323
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume72
Issue number15
DOIs
Publication statusPublished - 15 Oct 2005

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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