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Theoretical study on strain-induced variations in electronic properties of monolayer MoS2

Authors
  • Dong, Liang1
  • Namburu, Raju R.2
  • O’Regan, Terrance P.3
  • Dubey, Madan3
  • Dongare, Avinash M.1
  • 1 University of Connecticut, Department of Materials Science and Engineering and Institute of Materials Science, Storrs, CT, 06269, USA , Storrs (United States)
  • 2 U.S. Army Research Laboratory, Aberdeen Proving Ground, Computational and Information Sciences Directorate, Maryland, 21005, USA , Maryland (United States)
  • 3 U.S. Army Research Laboratory, Sensors and Electron Devices Directorate, Adelphi, MD, 20783, USA , Adelphi (United States)
Type
Published Article
Journal
Journal of Materials Science
Publisher
Springer-Verlag
Publication Date
Jun 20, 2014
Volume
49
Issue
19
Pages
6762–6771
Identifiers
DOI: 10.1007/s10853-014-8370-5
Source
Springer Nature
Keywords
License
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Abstract

Ultrathin MoS2 sheets and nanostructures are promising materials for electronic and optoelectronic devices as well as chemical catalysts. To expand their potential in applications, a fundamental understanding is needed of the electronic structure and carrier mobility as a function of strain. In this paper, the effect of strain on electronic properties of monolayer MoS2 is investigated using ab initio simulations based on density functional theory. Our calculations are performed in both infinitely large two-dimensional (2D) sheets and one-dimensional (1D) nanoribbons which are theoretically cut from the sheets with semiconducting [1¯100]\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ [\bar{1}100] $$\end{document} (armchair) edges. The 2D crystal is studied under biaxial strain, uniaxial strain, and uniaxial stress conditions, while the 1D nanoribbon is studied under a uniaxial stress condition. Our results suggest that the electronic bandgap of the 2D sheet experiences a direct-indirect transition under both tensile and compressive strains. Its bandgap energy (Eg) decreases under tensile strain/stress conditions, while for an in-plane compression, Eg is initially raised by a small amount and then decreased as the strain varies from 0 to −6 %. On the other hand, Eg at the semiconducting edges of monolayer MoS2 nanoribbons is relatively invariant under uniaxial stretches or compressions. The effective masses of electrons at the conduction band minimum (CBM) and holes at the valence band maximum (VBM) are generally decreased as the in-plane extensions or compressions become stronger, but abrupt changes occur when CBM or VBM shifts between different k-points in the first Brillouin zone.

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