Orbital-Driven Interfacial Coupling in 2D Ferroelectric van der Waals Metal–Semiconductor Junctions: A Route to Near-Quantum-Limit Contact Resistance

Abstract

van der Waals (vdW) metal–semiconductor junctions (MSJs) are promising for two-dimensional (2D) field-effect transistors, but efficient carrier injection is hindered by tunneling barriers arising from weak interfacial coupling. Here, we propose a strategy to achieve near-quantum-limit contacts by introducing strong interlayer interactions in vdW MSJs, combining bilayer MTe2 (M = Ni, Pd, Pt) electrodes with ferroelectric semiconductors. Confirmed by crystal orbital bond index and crystal orbital Hamilton population analyses, the vertically extended Te-pz orbitals of MTe2 facilitate pz-pz mixing across the interface, forming significant interfacial coupling that enhances tunneling efficiency up to 36.1% while preserving weak Fermi-level pinning (FLP). Under the synergistic effect of ferroelectric-tunable Schottky barriers, ultralow contact resistance down to 51.3 Ω·μm is achieved, approaching the quantum limit. This work highlights the pivotal role of orbital-driven coupling in optimizing vdW contacts, providing a foundational route toward FLP-suppressed low-resistance MSJs for next-generation nanoelectronics.