Revisiting the Schottky-Mott Relation for Metal/Transition Metal Dichalcogenide Interfaces: The Role of Interface Dipoles.

Chuu, Chih-Piao; Chang, Shu-Jui; Sheu, Yu-Miin; Huang, Zih-Syuan; Liu, Wei-Tung; Chen, Po-Wei; Chou, Sui-An; Lin, Yu-Tung et al. · ACS Nano · 2026

basic_science · Level V

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Abstract

High contact resistance, stemming from Fermi-level pinning (FLP), is a bottleneck in the contact engineering of transition metal dichalcogenide (TMD)-based two-dimensional field-effect transistors (2DFETs). Our study re-examines the nature of FLP in 2D semiconductors, focusing on regimes where the material thickness is commensurate with the interface thickness. By combining first-principles calculations with experimental validation via ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling spectroscopy (STS), we establish the metal effective work function (eWF) as a figure of merit for substantiating the Schottky-Mott relation. Our findings indicate that FLP is governed by both long-range dipole interactions and extended short-range Lennard-Jones potentials. This framework, in conjunction with the linear Schottky-Mott relation, improves predictive capabilities in contact engineering.