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Nat Nanotechnol. 2015 Jun;10(6):534-40. doi: 10.1038/nnano.2015.70. Epub 2015 Apr 27.

Multi-terminal transport measurements of MoS2 using a van der Waals heterostructure device platform.

Author information

1
Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA.
2
Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea.
3
School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
4
KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea.
5
Department of Material Science and Engineering, Columbia University, New York, New York 10027, USA.
6
Center for Nanostructured Graphene (CNG), DTU Nanotech, Technical University of Denmark, Ørsteds Plads, 345E, Kgs. Lyngby 2800, Denmark.
7
National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
8
1] School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA [2] Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA.
9
Department of Electrical &Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
10
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

Abstract

Atomically thin two-dimensional semiconductors such as MoS2 hold great promise for electrical, optical and mechanical devices and display novel physical phenomena. However, the electron mobility of mono- and few-layer MoS2 has so far been substantially below theoretically predicted limits, which has hampered efforts to observe its intrinsic quantum transport behaviours. Potential sources of disorder and scattering include defects such as sulphur vacancies in the MoS2 itself as well as extrinsic sources such as charged impurities and remote optical phonons from oxide dielectrics. To reduce extrinsic scattering, we have developed here a van der Waals heterostructure device platform where MoS2 layers are fully encapsulated within hexagonal boron nitride and electrically contacted in a multi-terminal geometry using gate-tunable graphene electrodes. Magneto-transport measurements show dramatic improvements in performance, including a record-high Hall mobility reaching 34,000 cm(2) V(-1) s(-1) for six-layer MoS2 at low temperature, confirming that low-temperature performance in previous studies was limited by extrinsic interfacial impurities rather than bulk defects in the MoS2. We also observed Shubnikov-de Haas oscillations in high-mobility monolayer and few-layer MoS2. Modelling of potential scattering sources and quantum lifetime analysis indicate that a combination of short-range and long-range interfacial scattering limits the low-temperature mobility of MoS2.

PMID:
25915194
DOI:
10.1038/nnano.2015.70

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