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Title: Atomistic modeling of the metallic-to-semiconducting phase boundaries in monolayer MoS{sub 2}

Abstract

Recent experimental demonstration on the coexistence of metallic and semiconducting phases in the same monolayer MoS{sub 2} crystal has attracted much attention for its use in ultra-low contact resistance-MoS{sub 2} transistors. However, the electronic structures of the metallic-to-semiconducting phase boundaries, which appear to dictate the carrier injection in such transistors, are not yet well understood. In this letter, interfacing the 2H and 1T′ polytypes appropriately, we first model the “beta” (β) and the “gamma” (γ) phase boundaries, and demonstrate good agreement with experiential results. We then apply first-principles based density functional theory to calculate the electronic structures for those optimized geometries. We further employ non equilibrium Green's function formalism to evaluate the transmission spectra and the local density of states (LDOS) in order to assess the Schottky barrier nature of the phase boundaries. Our study reveals that while the γ boundary yields p-type Schottky barrier, the β boundary leads to the distinct symmetric Schottky barrier with an atomically sharp transition region. This understanding could be useful for designing high performance transistors using phase-engineered MoS{sub 2} crystals.

Authors:
;  [1]
  1. Nano-Scale Device Research Laboratory, Department of Electronic Systems Engineering, Indian Institute of Science (IISc) Bangalore, Bangalore 560012 (India)
Publication Date:
OSTI Identifier:
22590825
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 108; Journal Issue: 25; 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; CRYSTALS; DENSITY; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; ELECTRONIC STRUCTURE; EQUILIBRIUM; MOLYBDENUM SULFIDES; SIMULATION; SPECTRA; SYMMETRY; TRANSISTORS

Citation Formats

Saha, Dipankar, E-mail: dipsah-etc@yahoo.co.in, and Mahapatra, Santanu, E-mail: santanu@dese.iisc.ernet.in. Atomistic modeling of the metallic-to-semiconducting phase boundaries in monolayer MoS{sub 2}. United States: N. p., 2016. Web. doi:10.1063/1.4954257.
Saha, Dipankar, E-mail: dipsah-etc@yahoo.co.in, & Mahapatra, Santanu, E-mail: santanu@dese.iisc.ernet.in. Atomistic modeling of the metallic-to-semiconducting phase boundaries in monolayer MoS{sub 2}. United States. doi:10.1063/1.4954257.
Saha, Dipankar, E-mail: dipsah-etc@yahoo.co.in, and Mahapatra, Santanu, E-mail: santanu@dese.iisc.ernet.in. Mon . "Atomistic modeling of the metallic-to-semiconducting phase boundaries in monolayer MoS{sub 2}". United States. doi:10.1063/1.4954257.
@article{osti_22590825,
title = {Atomistic modeling of the metallic-to-semiconducting phase boundaries in monolayer MoS{sub 2}},
author = {Saha, Dipankar, E-mail: dipsah-etc@yahoo.co.in and Mahapatra, Santanu, E-mail: santanu@dese.iisc.ernet.in},
abstractNote = {Recent experimental demonstration on the coexistence of metallic and semiconducting phases in the same monolayer MoS{sub 2} crystal has attracted much attention for its use in ultra-low contact resistance-MoS{sub 2} transistors. However, the electronic structures of the metallic-to-semiconducting phase boundaries, which appear to dictate the carrier injection in such transistors, are not yet well understood. In this letter, interfacing the 2H and 1T′ polytypes appropriately, we first model the “beta” (β) and the “gamma” (γ) phase boundaries, and demonstrate good agreement with experiential results. We then apply first-principles based density functional theory to calculate the electronic structures for those optimized geometries. We further employ non equilibrium Green's function formalism to evaluate the transmission spectra and the local density of states (LDOS) in order to assess the Schottky barrier nature of the phase boundaries. Our study reveals that while the γ boundary yields p-type Schottky barrier, the β boundary leads to the distinct symmetric Schottky barrier with an atomically sharp transition region. This understanding could be useful for designing high performance transistors using phase-engineered MoS{sub 2} crystals.},
doi = {10.1063/1.4954257},
journal = {Applied Physics Letters},
number = 25,
volume = 108,
place = {United States},
year = {Mon Jun 20 00:00:00 EDT 2016},
month = {Mon Jun 20 00:00:00 EDT 2016}
}
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