Beyond the heteroepitaxial quantum dot : self-assembling complex nanostructures controlled by strain and growth kinetics.
- Brookhaven National Laboratory, Upton, NY
- Hong Kong Polytechnic University, Hong Kong
- University of Virginia, Charlottesville, VA
- Texas A&M University, College Station, TX
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.
- Research Organization:
- Sandia National Laboratories
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 972135
- Report Number(s):
- SAND2005-3582J
- Journal Information:
- Proposed for publication in Physical Review B., Journal Name: Proposed for publication in Physical Review B.
- Country of Publication:
- United States
- Language:
- English
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