Strain distributionand electronic property modifications in Si/Ge axial nanowires hetrostructures


Molecular dynamics simulations were carried out for Si/Ge axial nanowire heterostructures using modified effective atom method (MEAM) potentials. A Si–Ge MEAM interatomic cross potential was developed based on available experimental data and was used for these studies. The atomic distortions and strain distributions near the Si/Ge interfaces are predicted for nanowires with their axes oriented along the [111] direction. The cases of 10 and 25 nm diameter Si/Ge biwires and of 25 nm diameter Si/Ge/Si axial heterostructures with the Ge disk 1 nm thick were studied. Substantial distortions in the height of the atoms adjacent to the interface were found for the biwires but not for the Ge disks. Strains as high as 3.5% were found for the Ge disk and values of 2%–2.5% were found at the Si and Ge interfacial layers in the biwires. Deformation potential theory was used to estimate the influence of the strains on the band gap, and reductions in band gap to as small as 40% of bulk values are predicted for the Ge disks. The localized regions of increased strain and resulting energy minima were also found within the Si/Ge biwire interfaces with the larger effects on the Ge side of the interface. The regions of strain maxima near and within the interfaces are anticipated to be useful for tailoring band gaps and producing quantum confinement of carriers. These results suggest that nanowire heterostructures provide greater design flexibility in band structure modification than is possible with planar layer growth.

Publication DOI:
Divisions: College of Engineering & Physical Sciences > School of Engineering and Technology > Mechanical, Biomedical & Design
College of Engineering & Physical Sciences
Additional Information: © 2009 American Institute of Physics. Citation: Journal of Applied Physics 105, 044310 (2009); doi: 10.1063/1.3077293
Uncontrolled Keywords: deformation,elemental semiconductors,energy gap,germanium,interface states,interface structure,molecular dynamics method,nanowires,semiconductor growth,semiconductor heterojunctions,semiconductor quantum wires,silicon,General Physics and Astronomy
Publication ISSN: 1089-7550
Last Modified: 27 Jun 2024 07:49
Date Deposited: 24 Apr 2012 13:08
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
http://link.aip ... ?jap/105/044310 (Publisher URL)
PURE Output Type: Article
Published Date: 2009-02-15
Authors: Swadener, J. Greg (ORCID Profile 0000-0001-5493-3461)
Picraux, S.T.



Version: Published Version

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