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Nano Lett. 2015 May 13;15(5):3030-4. doi: 10.1021/nl504957p. Epub 2015 Apr 22.

Toward barrier free contact to molybdenum disulfide using graphene electrodes.

Author information

1
†Department of Materials Science and Engineering, ‡Department of Chemistry and Biochemistry, and §California Nanosystems Institute, University of California, Los Angeles, California 90095, United States.

Abstract

Two-dimensional layered semiconductors such as molybdenum disulfide (MoS2) have attracted tremendous interest as a new class of electronic materials. However, there are considerable challenges in making reliable contacts to these atomically thin materials. Here we present a new strategy by using graphene as the back electrodes to achieve ohmic contact to MoS2. With a finite density of states, the Fermi level of graphene can be readily tuned by a gate potential to enable a nearly perfect band alignment with MoS2. We demonstrate for the first time a transparent contact to MoS2 with zero contact barrier and linear output behavior at cryogenic temperatures (down to 1.9 K) for both monolayer and multilayer MoS2. Benefiting from the barrier-free transparent contacts, we show that a metal-insulator transition can be observed in a two-terminal MoS2 device, a phenomenon that could be easily masked by Schottky barriers found in conventional metal-contacted MoS2 devices. With further passivation by boron nitride (BN) encapsulation, we demonstrate a record-high extrinsic (two-terminal) field effect mobility up to 1300 cm(2)/(V s) in MoS2 at low temperature.

KEYWORDS:

MoS2; barrier free; graphene contact; high mobility; layered materials; ohmic contact

PMID:
25879371
DOI:
10.1021/nl504957p
[Indexed for MEDLINE]

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