Heteroepitaxial self-assembly of higher-complexity structures by combining growth control with nanopatterning

Jerrold A. Floro, Jennifer L. Gray, Surajit Atha, Nitin Singh, Dana Elzey, Robert Hull

Research output: Contribution to journalConference articlepeer-review


We provide an overview of a novel self-assembly process that occurrs during GeSi/Si(001) strain-layer heteroepitaxy under conditions of limited adatom mobility. Suppression of copious surface diffusion leads to limited three-dimensional roughening in the form of pits that partially consume a thick, metastable wetting layer. The material ejected from the pits accumulates alongside, eventually forming a symmetric quantum dot molecule consisting of four islands bound to a {105}-faceted pit. These structures, which are of interest in nanologic applications, appear to arise from an intrinsic strainrelief mechanism in a relatively narrow regime of deposition conditions. An additional degree of morphological control is obtained by annealing films containing pits, before they evolve to full quantum dot molecules. Annealing promotes a one-dimensional growth instability leading to the formation of highly anisotropic grooves, bounded by long, wire-like islands. Finally, we show that patterns created in the Si substrate using a focused ion beam can control the location of quantum dot molecules, which is an additional critical step towards being able to use these structures for computing.

Original languageEnglish (US)
Article numberKK4.3
Pages (from-to)1-11
Number of pages11
JournalMaterials Research Society Symposium Proceedings
StatePublished - 2005
Event2004 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 29 2004Dec 2 2004

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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