Controlling Gold-Assisted Exfoliation of Large-Area MoS2 Monolayers with External Pressure

Controlling Gold-Assisted Exfoliation of Large-Area MoS2 Monolayers with External Pressure

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Gold-assisted exfoliation can fabricate centimeter- or larger-sized monolayers of van der Waals (vdW) semiconductors, which is desirable for their applications in electronic and optoelectronic devices.However, there is still a lack of control over the menthol kangvape exfoliation processes and a limited understanding of the atomic-scale mechanisms.Here, we tune the MoS2-Au interface using controlled external pressure and reveal two atomic-scale prerequisites for successfully producing large-area monolayers of MoS2.The first is the formation of strong MoS2-Au interactions to anchor the top MoS2 monolayer to the Au surface.The second is the integrity of the covalent network of the monolayer, as the majority of the monolayer is non-anchored and relies on the covalent network to be exfoliated from the bulk MoS2.

Applying pressure or using smoother Au films increases the MoS2-Au interaction, but may cause the covalent network of the MoS2 monolayer to break due to excessive lateral strain, resulting in nearly zero exfoliation yield.Scanning tunneling microscopy measurements of the MoS2 monolayer-covered Au show that even the smallest atomic-scale imperfections can disrupt the MoS2-Au interaction.These findings can be used to develop new strategies for fabricating vdW monolayers through metal-assisted exfoliation, such as in cases involving patterned dale duby obsidian knives or non-uniform surfaces.