Scalable Transfer of Suspended Two-Dimensional Single Crystals

Abstract

Large-scale suspended architectures of various two-dimensional (2D) materials (MoS₂, MoSe₂, WS₂, and graphene) are demonstrated on nanoscale patterned substrates with different physical and chemical surface properties, such as flexible polymer substrates (polydimethylsiloxane), rigid Si substrates, and rigid metal substrates (Au/Ag). This transfer method represents a generic, fast, clean, and scalable technique to suspend 2D atomic layers. The underlying principle behind this approach, which employs a capillary-force-free wet-contact printing method, was studied by characterizing the nanoscale solid–liquid–vapor interface of 2D layers with respect to different substrates. As a proof-of-concept, a photodetector of suspended MoS₂ has been demonstrated with significantly improved photosensitivity. This strategy could be extended to several other 2D material systems and open the pathway toward better optoelectronic and nanoelectromechnical systems