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Title: Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes

Abstract

Ultrathin two-dimensional semiconductors obtained from layered transition-metal dichalcogenides such as molybdenum disulfide (MoS{sub 2}) are promising for ultimately scaled transistors beyond Si. Although the shortening of the semiconductor channel is widely studied, the narrowing of the channel, which should also be important for scaling down the transistor, has been examined to a lesser degree thus far. In this study, the impact of narrowing on mechanically exfoliated MoS{sub 2} flakes was investigated according to the channel-width-dependent Schottky barrier heights at Cr/Au contacts. Narrower channels were found to possess a higher Schottky barrier height, which is ascribed to the edge-induced band bending in MoS{sub 2}. The higher barrier heights degrade the transistor performance as a higher electrode-contact resistance. Theoretical analyses based on Poisson's equation showed that the edge-induced effect can be alleviated by a high dopant impurity concentration, but this strategy should be limited to channel widths of roughly 0.7 μm because of the impurity-induced charge-carrier mobility degradation. Therefore, proper termination of the dangling bonds at the edges should be necessary for aggressive scaling with layered semiconductors.

Authors:
 [1]
  1. Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, Sakai 599-8570 (Japan)
Publication Date:
OSTI Identifier:
22597669
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 120; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BENDING; CARRIER MOBILITY; CHARGE CARRIERS; CONCENTRATION RATIO; DOPED MATERIALS; ELECTRODES; IMPURITIES; MODULATION; MOLYBDENUM; MOLYBDENUM SULFIDES; POISSON EQUATION; SCALING; SCHOTTKY BARRIER DIODES; SEMICONDUCTOR MATERIALS; SILICON OXIDES; TRANSISTORS; TWO-DIMENSIONAL CALCULATIONS; WIDTH

Citation Formats

Nouchi, Ryo. Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes. United States: N. p., 2016. Web. doi:10.1063/1.4960703.
Nouchi, Ryo. Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes. United States. doi:10.1063/1.4960703.
Nouchi, Ryo. Sun . "Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes". United States. doi:10.1063/1.4960703.
@article{osti_22597669,
title = {Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes},
author = {Nouchi, Ryo},
abstractNote = {Ultrathin two-dimensional semiconductors obtained from layered transition-metal dichalcogenides such as molybdenum disulfide (MoS{sub 2}) are promising for ultimately scaled transistors beyond Si. Although the shortening of the semiconductor channel is widely studied, the narrowing of the channel, which should also be important for scaling down the transistor, has been examined to a lesser degree thus far. In this study, the impact of narrowing on mechanically exfoliated MoS{sub 2} flakes was investigated according to the channel-width-dependent Schottky barrier heights at Cr/Au contacts. Narrower channels were found to possess a higher Schottky barrier height, which is ascribed to the edge-induced band bending in MoS{sub 2}. The higher barrier heights degrade the transistor performance as a higher electrode-contact resistance. Theoretical analyses based on Poisson's equation showed that the edge-induced effect can be alleviated by a high dopant impurity concentration, but this strategy should be limited to channel widths of roughly 0.7 μm because of the impurity-induced charge-carrier mobility degradation. Therefore, proper termination of the dangling bonds at the edges should be necessary for aggressive scaling with layered semiconductors.},
doi = {10.1063/1.4960703},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 6,
volume = 120,
place = {United States},
year = {2016},
month = {8}
}