Dry Exfoliation of Large-Area 2D Monolayer and Heterostructure Arrays

Two-dimensional (2D) semiconductors have attracted considerable attention in recent years. However, to date, there is still no effective approach to produce large-scale monolayers while retaining their intrinsic properties. Here, we report a simple mechanical exfoliation method to produce large-scale and high-quality 2D semiconductors, by designing an atomically flat Au-mesh film as the peeling tape. Using our prefabricated mesh tape, the limited contact region (between the 2D crystal and Au) could provide enough adhesion to mechanically exfoliate uniform 2D monolayers, and the noncontact region (between the mesh holes and monolayers) ensures weak interaction to mechanically release the 2D monolayers on desired substrates. Together, we demonstrate a scalable method to dry exfoliate various 2D monolayer arrays onto different substrates without involving any solutions or contaminations, representing the optimization between material yield, scalability, and quality. Furthermore, detailed optical and electrical characterizations are conducted to confirm their intrinsic quality. With the ability to mechanically exfoliate various 2D arrays and further restacking them, we have demonstrated large-scale van der Waals heterostructure arrays through layer-to-layer assembling. Our study offers a simple and scalable method for dry exfoliating 2D monolayer and heterostructure arrays with intrinsic material quality, which could be crucial to accelerate fundamental investigations as well as practical applications of proof-of-concepts devices.