Abstract

We report a deterministic 2D material (2DM) transfer method to assemble any-stacking-order heterostructures incorporating suspended ultra-thin 2D materials, such as single (SLG) and bilayer graphene (BLG). This high-yield and facile transfer method will enable fabrication of 2DM heterostructures suited for nano-opto-electromechanical (NOEMS) studies, such as optical transducers where a small gate voltage moves a suspended 2DM to vastly enhance or suppress its exclusive light absorption. Our transfer procedure is based on a 3 dimensional (3D) nitrocellulose micro-stamp which can dry pick-up single and naked 2DMs (graphene, MoS2, and hBN) directly from a SiO2 substrate, and deterministically transfer them on substrates or suspend them over trenches. Optical and Raman spectroscopy show that no significant defects and doping is introduced upon transfer, even in suspended SLG and BLG. The transferred area of ultra-thin 2D crystals ranges up to 600 μm2. The suspension procedure does not require critical point drying, and transfers ultra-thin 2DM areas up to 15 μm2 with suspension heights down to 550 nm. Using this fabrication method,
we assembled optical cavities able to accurately tune the Raman scattering intensity and exclusive light absorption on both on substrate and suspended BLG by factors of 19 and 4 respectively. This deterministic fabrication of heterostructures incorporating
suspended 2DMs is likely to accelerate research in twistronics, straintronics and NOEMS.