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Title: Theory of multiple quantum dot formation in strained-layer heteroepitaxy

Abstract

We develop a theory for the experimentally observed formation of multiple quantum dots (QDs) in strained-layer heteroepitaxy based on surface morphological stability analysis of a coherently strained epitaxial thin film on a crystalline substrate. Using a fully nonlinear model of surface morphological evolution that accounts for a wetting potential contribution to the epitaxial film's free energy as well as surface diffusional anisotropy, we demonstrate the formation of multiple QD patterns in self-consistent dynamical simulations of the evolution of the epitaxial film surface perturbed from its planar state. The simulation predictions are supported by weakly nonlinear analysis of the epitaxial film surface morphological stability. We find that, in addition to the Stranski-Krastanow instability, long-wavelength perturbations from the planar film surface morphology can trigger a nonlinear instability, resulting in the splitting of a single QD into multiple QDs of smaller sizes, and predict the critical wavelength of the film surface perturbation for the onset of the nonlinear tip-splitting instability. The theory provides a fundamental interpretation for the observations of “QD pairs” or “double QDs” and other multiple QDs reported in experimental studies of epitaxial growth of semiconductor strained layers and sets the stage for precise engineering of tunable-size nanoscale surface features inmore » strained-layer heteroepitaxy by exploiting film surface nonlinear, pattern forming phenomena.« less

Authors:
;  [1]
  1. Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003-9303 (United States)
Publication Date:
OSTI Identifier:
22590604
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 2; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; DISTURBANCES; EPITAXY; FREE ENERGY; INSTABILITY; LAYERS; NONLINEAR PROBLEMS; QUANTUM DOTS; SEMICONDUCTOR MATERIALS; SIMULATION; STRAINS; SURFACES; THIN FILMS; WAVELENGTHS

Citation Formats

Du, Lin, and Maroudas, Dimitrios, E-mail: maroudas@ecs.umass.edu. Theory of multiple quantum dot formation in strained-layer heteroepitaxy. United States: N. p., 2016. Web. doi:10.1063/1.4955409.
Du, Lin, & Maroudas, Dimitrios, E-mail: maroudas@ecs.umass.edu. Theory of multiple quantum dot formation in strained-layer heteroepitaxy. United States. doi:10.1063/1.4955409.
Du, Lin, and Maroudas, Dimitrios, E-mail: maroudas@ecs.umass.edu. Mon . "Theory of multiple quantum dot formation in strained-layer heteroepitaxy". United States. doi:10.1063/1.4955409.
@article{osti_22590604,
title = {Theory of multiple quantum dot formation in strained-layer heteroepitaxy},
author = {Du, Lin and Maroudas, Dimitrios, E-mail: maroudas@ecs.umass.edu},
abstractNote = {We develop a theory for the experimentally observed formation of multiple quantum dots (QDs) in strained-layer heteroepitaxy based on surface morphological stability analysis of a coherently strained epitaxial thin film on a crystalline substrate. Using a fully nonlinear model of surface morphological evolution that accounts for a wetting potential contribution to the epitaxial film's free energy as well as surface diffusional anisotropy, we demonstrate the formation of multiple QD patterns in self-consistent dynamical simulations of the evolution of the epitaxial film surface perturbed from its planar state. The simulation predictions are supported by weakly nonlinear analysis of the epitaxial film surface morphological stability. We find that, in addition to the Stranski-Krastanow instability, long-wavelength perturbations from the planar film surface morphology can trigger a nonlinear instability, resulting in the splitting of a single QD into multiple QDs of smaller sizes, and predict the critical wavelength of the film surface perturbation for the onset of the nonlinear tip-splitting instability. The theory provides a fundamental interpretation for the observations of “QD pairs” or “double QDs” and other multiple QDs reported in experimental studies of epitaxial growth of semiconductor strained layers and sets the stage for precise engineering of tunable-size nanoscale surface features in strained-layer heteroepitaxy by exploiting film surface nonlinear, pattern forming phenomena.},
doi = {10.1063/1.4955409},
journal = {Applied Physics Letters},
number = 2,
volume = 109,
place = {United States},
year = {Mon Jul 11 00:00:00 EDT 2016},
month = {Mon Jul 11 00:00:00 EDT 2016}
}