Abstract
Exfoliation of large-area monolayers is important for fundamental research and technological implementation of transition-metal dichalcogenides. Various techniques have been explored to increase the exfoliation yield, but little is known about the underlying mechanism at the atomic level. Here, we demonstrate gold-assisted mechanical exfoliation of monolayer molybdenum disulfide, up to a centimeter scale. Detailed spectroscopic, microscopic, and first-principles density functional theory analyses reveal that strong van der Waals (vdW) interaction between Au and the topmost MoS2 layer facilitates the exfoliation of monolayers. However, the large-area exfoliation promoted by such strong vdW interaction is only achievable on freshly prepared clean and smooth Au surfaces, while rough surfaces and surfaces exposed to air for more than 15 min result in negligible exfoliation yields. This technique is successfully extended to MoSe2, WS2, WSe2, MoTe2, WTe2, and GaSe. In addition, electrochemical characterization reveals intriguing interactions between monolayer MoS2 and Au. A subnanometer-thick MoS2 monolayer strongly passivates the chemical properties of the underlying Au, and the Au significantly modulates the electronic band structure of the MoS2, turning it from semiconducting to metallic. This could find applications in many areas, including electrochemistry, photovoltaics, and photocatalysis.
Original language | English |
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Pages (from-to) | 10463-10472 |
Journal | ACS Nano |
Volume | 12 |
Issue number | 10 |
Early online date | 28 Sep 2018 |
DOIs | |
Publication status | Early online date - 28 Sep 2018 |
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Dive into the research topics of 'Mechanism of Gold-Assisted Exfoliation of Centimeter-Sized Transition-Metal Dichalcogenide Monolayers'. Together they form a unique fingerprint.Student Theses
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MoS2 on Gold: Achieving extremely high exfoliation yield and optical contrast for Van der Waals monolayers
Author: Donnelly, G., Dec 2020Supervisor: Felton, S. (Supervisor) & Huang, F. (Supervisor)
Student thesis: Doctoral Thesis › Doctor of Philosophy
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Profiles
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Fumin Huang
- School of Mathematics and Physics - Senior Lecturer
- Centre for Nanostructured Media (CNM)
Person: Academic