Robust van der Waals Metal Mask for Residue‐Free and All‐Solid 2D Material Engineering

Abstract The van der Waals (vdW) contact, characterized by its bondless interactions, opens up exciting possibilities in cutting‐edge mask technology. It enables incredibly close proximity to samples at the atomic level while facilitating non‐destructive engineering. In this study, the concept of a vdW metal mask using the template striped ultra‐flat Ag/Au film is introduced. The probe tip‐assisted metal film transfer under an optical microscope is employed to showcase all‐solid and residue‐free engineering on 2D materials. The robust nature of the vdW metal mask allows for various treatments, including gas, liquid, solid, plasma, and light, making it a universal tool for fabricating 2D material‐based devices and samples with sub‐1 µm resolution, all without the need for lithography technologies. With the superiority in simple sample fabrication, ultra‐clean surfaces, and robustness under harsh conditions, the technique is believed to flourish in the 2D material research field.