Quantitative Model of Heterogeneous Nucleation and Growth of SiGe Quantum Dot Molecules

Hao Hu, Hongjun Gao, and Feng Liu
Phys. Rev. Lett. 109, 106103 – Published 7 September 2012
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Using a multiscale approach combining continuum model with first-principles calculation, we develop a quantitative theoretical model for heterogeneous nucleation and the growth of a quantum dot molecule—a few islands “strain bonded” by a pit in heteroepitaxy of thin films, in contrast to homogeneous nucleation and growth of isolated strain islands on the surface. We show that the critical size and energy barrier for island nucleation next to a pit is substantially reduced with the increasing pit size, but the reduction approaches an upper bound of 85% and 72% for the size and barrier, respectively. Our model also predicts a self-limiting effect on island growth, resulting from an intriguing interplay between island-pit attraction and island-island repulsion, that drives the island size to increase linearly with the pit size, which explains a long-standing puzzle of experimental observation.

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  • Received 8 May 2012


© 2012 American Physical Society

Authors & Affiliations

Hao Hu1,2, Hongjun Gao2, and Feng Liu1,*

  • 1Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA
  • 2Institute of Physics, Chinese Academy of Science, Beijing 100190, China

  • *Corresponding author: fliu@eng.utah.edu

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Vol. 109, Iss. 10 — 7 September 2012

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