Tunneling transport in a few monolayer-thick WS2/graphene heterojunction

Abstract

This paper demonstrates the high-quality tunnel barrier characteristics and layer number controlled tunnel resistance of a transition metal dichalcogenide (TMD) measuring just a few monolayers in thickness. Investigation of vertical transport in WS2 and MoS2 TMDs in graphene/TMD/metal heterostructures revealed that WS2 exhibits tunnel barrier characteristics when its thickness is between 2 to 5 monolayers, whereas MoS2 experiences a transition from tunneling to thermionic emission transport with increasing thickness within the same range. Tunnel resistance in a graphene/WS2/metal heterostructure therefore increases exponentially with the number of WS2 layers, revealing the tunnel barrier height of WS2 to be 0.37 eV.

15 pages, 3 figures

References in corpus (5)

• Boron nitride substrates for high-quality graphene electronics
• Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
• Atomically thin boron nitride: a tunnelling barrier for graphene devices
• Quantum Hall effect and Landau level crossing of Dirac fermions in trilayer graphene
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• Influence of the density of states of graphene on the transport properties of graphene/MoS2/metal vertical field-effect transistors
• Ultralow Schottky Barriers in hBN-Encapsulated Monolayer WSe${}_2$ Tunnel Field-Effect Transistors
• Detection of cyclotron resonance using photo-induced thermionic emission at graphene/MoS2 van der Waals interface