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Updated: Jun 11, 2026

Plasma-assisted Molecular Beam Epitaxy of N-polar InAlN-barrier High-electron-mobility Transistors
Published on: November 24, 2016
Fermi-level depinning achieved by high-work-function Au1-xSex alloy contacts for high-performance p-type WSe2
Wanying Li1, Yipu Xia2, Yuanhao Kou3
1Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore.
Abstract:
P-type contact in two-dimensional (2D) transition metal dichalcogenides (TMDs) faces more severe Fermi-level pinning (FLP) than their n-type counterparts due to the damage caused by high-work-function metal deposition. Here, we demonstrate a simple molecular beam epitaxy (MBE) contact strategy using a high-work-function (5.8 eV) Au1-xSex alloy to achieve Fermi-level depinning in monolayer WSe2 p-type transistors. The Au1-xSex alloy mitigates both defect-induced gap states (DIGS) and metal-induced gap states (MIGS) by gentle pre-deposition of selenium (Se) followed by the conversion to Au1-xSex alloy by deposition of Au at low-temperature, forming a van der Waals (vdW) interface between Au1-xSex and monolayer WSe2. Moreover, it imposes hole doping to the contacted monolayer WSe2, reducing the Schottky barrier height and enabling favorable p-type device performance. Combined experimental and theoretical analyses confirm quasi-ohmic contact behavior, yielding a contact resistance of 492 Ω·µm, an on-current of 385 µA/µm, and an on/off ratio greater than 108 for a p-FET with a 100 nm channel length. This work establishes Au1-xSex alloy contacts as a scalable solution for high-performance p-type 2D electronics.
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