Ohmic-to-Schottky Conversion in Monolayer Tellurene–Metal Interface via Graphene Insertion

Abstract

Tellurene, a relatively new addition to the two-dimensional (2D) material family, has shown promising prospect in future nanoelectronics. Atomistic understanding of the electronic properties of 2D material-metal interfaces is crucial to promote optimal device performance. Monolayer tellurene exhibits an unusual Ohmic nature when interfaced with any metal surfaces, restricting its applications in vertical Schottky barrier devices. Using density functional theory (DFT), here, we describe a technique of adding a buffer layer to prevent the formation of Ohmic contact. Using six different metals (Ag, Au, Pt, Pd, Ru, and Ti), we show that the insertion of a graphene layer between tellurene and a metal surface can screen the metallization of tellurene and create Schottky barriers. The Schottky barrier heights (SBHs) can be now modulated using metal electrodes with different work functions (WFs) because the graphene layer partially depins the Fermi level. Our study provides quantum-chemical insights into the realization of vertical Schottky diodes using monolayer tellurene that could be a key component in future high-frequency nanoelectronic devices. © 2021 American Chemical Society.