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.