Open Access Nano Express

Superlattice Growth via MBE and Green’s Function Techniques

JJ Ramsey1*, Ernian Pan1, Peter W Chung2 and Zhiming M Wang3

Author Affiliations

1 College of Engineering, University of Akron, 302 Buchtel Common, Akron, OH, 44325, USA

2 U.S. Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD, 21005, USA

3 Institute of Nanoscale Science and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA

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Nanoscale Research Letters 2010, 5:1272-1278  doi:10.1007/s11671-010-9636-8

Published: 19 May 2010

Abstract

A model has been developed to simulate the growth of arrays consisting of a substrate on which alternating layers of quantum dots (QDs) and spacer layers are epitaxially grown. The substrate and spacer layers are modeled as an anisotropic elastic half-space, and the QDs are modeled as point inclusions buried within the half-space. In this model, the strain at the free surface of this half-space due to the buried point QDs is calculated, and a scalar measure of the strain at the surface is subsequently determined. New point QDs are placed on the surface where the previously calculated scalar strain measure is a minimum. Following available DFT results, this scalar strain measure is a weighted average of the in-plane strains. This model is constructed under the assumption that diffusional anisotropy can be neglected, and thus, the results are more in agreement with results from experiments of growth of SiGe QDs than experiments involving QDs of (In,Ga)As.

Keywords:
Quantum dots; Green’s function; Surface diffusion; Anisotropy