Interfacial Properties of Monolayer MoSe2-Metal Contacts

Monolayer (ML) transition-metal dichalcogenides are considered as promising channel materials in next-generation transistors. Using ab initio energy band calculations and more reliable ab initio quantum transport simulations, we study the interfacial properties of ML MoSe2 - metal interfaces (metals = Al, Ag, Pt, Cr, Ni, and Ti). Weak or medium adsorption is found between ML MoSe2 and the Al, Ag, and Pt surfaces with the band structure of ML MoSe2 preserved, while strong adsorption is found between ML MoSe2 and the Ni, Ti, and Cr surfaces with the band structure of ML MoSe2 destroyed. The two methods give similar polarity and height of Schottky barriers for ML MoSe2 with Al, Ag, Pt, and Ti electrodes. ML MoSe2 forms an n-type Schottky contact with Ag, Ti, and Al electrodes with electron Schottky barrier heights (SBH) of 0.25, 0.29, and 0.56 eV, respectively, and a p-type Schottky contact with Pt electrode with hole SBH of 0.78 eV according to ab initio quantum transport simulations. Our study offers a guidance for the choices of suitable metal electrodes in ML MoSe2 devices.