Au‐mediated exfoliation of 2D transition‐metal dichalcogenides (TMDs) has received significant attention due to its ability to produce large‐area monolayer (ML) flakes. This process has been attributed to strong TMD/Au binding energy (BE) as well as the uniform strain between the TMDs and Au. However, large‐area exfoliation of TMDs with other metals that have even stronger theoretical BE than Au/TMD is not successful, leading to question whether the BE plays any role in the exfoliation process. Here, successful demonstration of large‐area ML MoS2using Cu, Ni, and Ag with various predicted strain, including Pd with almost no strain, but stronger BE than Au/MoS2is demonstrated. Optical micrographs show MoS2flakes with 100s of µm in size with a yield of several tens to hundreds of ML flakes per exfoliation. Photoluminescence and Raman spectroscopy confirm the ML nature of the flakes, while electrical transport measurements show mobilities of
Mechanical exfoliation yields high‐quality 2D materials but is challenging to scale up due to the small lateral size and low yield of the exfoliated crystals. Gold‐mediated exfoliation of macroscale monolayer MoS2and related crystals addresses this problem. However, it remains unclear whether this method can be extended to other metals. Herein, mechanical exfoliation of MoS2on a range of metallic substrates is studied. It is found that Au outperforms all the other metals in their ability to exfoliate macroscale monolayer MoS2. This is rationalized by gold's ability to resist oxidation, which is compromised on other metals and leads to a weakened binding with MoS2. An anomalously high monolayer yield found for Ag suggests that the large interfacial strain in the metal–MoS2heterostructures measured by Raman spectroscopy also is a critical factor facilitating the exfoliation, while the relative differences in the metal–MoS2binding play only a minor role. These results provide a new incentive for investigations of 2D material‐substrate combinations applicable where high‐quality 2D crystals of macroscopic dimensions are of importance.
more » « less- NSF-PAR ID:
- 10455889
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 7
- Issue:
- 23
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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