Controlling the Schottky barrier at MoS2|metal contacts by inserting a BN monolayer

Abstract

Making a metal contact to the two-dimensional semiconductor MoS2 without creating a Schottky barrier is a challenge. Using density functional calculations we show that, although the Schottky barrier for electrons obeys the Schottky-Mott rule for high work function ($\gtrsim 4.7$ eV) metals, the Fermi level is pinned at 0.1-0.3 eV below the conduction band edge of MoS2 for low work function metals, due to the metal-MoS2 interaction. Inserting a boron nitride (BN) monolayer between the metal and the MoS2 disrupts this interaction, and restores the MoS2 electronic structure. Moreover, a BN layer decreases the metal work function of Co and Ni by $\sim 2$ eV, and enables a line-up of the Fermi level with the MoS2 conduction band. Surface modification by adsorbing a single BN layer is a practical method to attain vanishing Schottky barrier heights.

5 pages, 5 figures

References in corpus (7)

• Integrated Circuits Based on Bilayer MoS2 Transistors
• Quasiparticle band structures and optical properties of strained monolayer MoS2 and WS2
• Channel Length Scaling of MoS2 MOSFETs
• Electron-hole transport and photovoltaic effect in gated MoS2 Schottky junctions
• Magnetoresistive junctions based on epitaxial graphene and hexagonal boron nitride
• Indirect doping effects from impurities in MoS${}_2$/BN heterostructures
• Large potential steps at weakly interacting metal-insulator interfaces

Cited by in corpus (7)

• Large valley splitting in monolayer WS${}_2$ by proximity coupling to an insulating antiferromagnetic substrate
• Gate-tunable black phosphorus spin valve with nanosecond spin lifetimes
• van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices
• Direct Opto-Electronic Imaging of 2D Semiconductor - 3D Metal Buried Interfaces
• Giant proximity exchange and valley splitting in transition metal dichalcogenide/$h\mathrm{BN}$/(Co, Ni) heterostructures
• Fermi level depinning via insertion of a graphene buffer layer at the gold-2D tin monoxide contact
• Study of gold and bismuth electrical contacts to a MoS${}_2$ monolayer