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Layer-dependent band offsets in metal/few-layer two-dimensional semiconductor junctions: Mechanisms and implications

Xiao-Lin Zhao*, Nie-Wei Wang*, Han Zhang, Nuo Xu, Rui-Ning Wang, Jiang-Long Wang†, and Xing-Qiang Shi‡

  • Hebei Research Center of the Basic Discipline for Computational Physics, Key Laboratory of Optic-Electronic Information and Materials of Hebei Province, College of Physics Science and Technology, Hebei University, Baoding 071002, People's Republic of China

  • *These authors contributed equally to this work.
  • †Contact author: jlwang@hbu.edu.cn
  • ‡Contact author: shixq20hbu@hbu.edu.cn
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Phys. Rev. Research 8, 023169 – Published 15 May, 2026

DOI: https://doi.org/10.1103/68cd-2nbh

Abstract

For electronic devices based on two-dimensional semiconductors (2DSs), few-layer transition-metal dichalcogenides offer enhanced electrical performance over their monolayer counterparts. Metal-semiconductor junctions (MSJs), which lie at the heart of such devices, incorporate not only a metal-semiconductor (M-S) interface but also multiple van der Waals semiconductor-semiconductor (S-S) interfaces when few-layer 2DSs are employed. However, the role of S-S interfaces within MSJs—particularly their interplay with the M-S interface and their potential device applications—remains poorly understood. Here, based on density-functional theory calculations, we conduct a systematic investigation of MSJs based on few-layer 2DSs (MoS2 and InSe) contacted with both two- and three-dimensional metals. We find layer-dependent band offsets between adjacent 2DS layers, which can change sign depending on the proximity to the metal contact. This spatial variation directly results in quantized band bending that deviates from classical models. These phenomena are attributed to the interplay and competition among three effects: (1) the decay of interface dipole with distance from the M-S interface, leading to layer-resolved band bending; (2) the interlayer quasibonding mixes up the energy levels between different 2DS layers, thereby affecting the band bending; and (3) screening by partially metallized 2DS layers within the junction, which can alter the direction of band bending. Leveraging these insights, we provide an understanding of the density-functional theory calculated Schottky barrier height values for few-layer 2DSs in MSJs. Additionally, we demonstrate that the interlayer band offset can suppress direct tunneling in vertical field-effect transistors based on 2DSs.

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Phys. Rev. Research 8, 023169– Published 15 May, 2026
  • Received 15 September 2025
  • Accepted 25 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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