Barrier-Free Carrier Injection in 2D WSe<sub>2</sub>-MoSe<sub>2</sub> Heterostructures via Fermi-Level Depinning

Fermi-level pinning (FLP) at metal–semiconductor interfaces remains a key obstacle to achieving low-resistance contacts in two-dimensional (2D) transition metal dichalcogenide (TMDC)-based heterostructures. Here, we present a first-principles study of Schottky barrier formation in WSe<sub>2<...

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Main Authors: Tian-Jun Dai, Xiang Xiao, Zhong-Yuan Fan, Zi-Yan Zhang, Yi Zhou, Yong-Chi Xu, Jian Sun, Xue-Fei Liu
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/13/1035
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Summary:Fermi-level pinning (FLP) at metal–semiconductor interfaces remains a key obstacle to achieving low-resistance contacts in two-dimensional (2D) transition metal dichalcogenide (TMDC)-based heterostructures. Here, we present a first-principles study of Schottky barrier formation in WSe<sub>2</sub>-MoSe<sub>2</sub> van der Waals heterostructures interfaced with four representative metals (Ag, Al, Au, and Pt). It was found that all metal–WSe<sub>2</sub>/MoSe<sub>2</sub> direct contacts induce pronounced metal-induced gap states (MIGSs), leading to significant FLP inside the WSe<sub>2</sub>/MoSe<sub>2</sub> band gaps and elevated Schottky barrier heights (SBHs) greater than 0.31 eV. By introducing a 2D metal-doped metallic (mWSe/mMoSe) layer between WSe<sub>2</sub>/MoSe<sub>2</sub> and the metal electrodes, the MIGSs can be effectively suppressed, resulting in nearly negligible SBHs for both electrons and holes, with even an SBH of 0 eV observed in the Ag-AgMoSe-MoSe<sub>2</sub> contact, thereby enabling quasi-Ohmic contact behavior. Our results offer a universal and practical strategy to mitigate FLP and achieve high-performance TMDC-based electronic devices with ultralow contact resistance.
ISSN:2079-4991