Polymethyl Methacrylate (PMMA) Pyrolysis Assisted Transfer of 2D Materials for Large-Scale Molybdenum Disulfide Nems Resonator Arrays

We develop a novel fabrication technique for large-scale two-dimensional (2D) molybdenum disulfide (MoS2) nanoelectromechanical resonator arrays, based on polymethyl methacrylate (PMMA) pyrolysis. During the transfer process, centimeter-scale monolayer MoS2 film grown by chemical vapor deposition (CVD) is covered with PMMA film by spin coating, delaminated from the growth substrate in water, and then transferred onto the pre-patterned substrate with surface microtrenches and contact electrodes. The PMMA is then removed by pyrolysis, or thermal decomposition in a furnace in vacuum, leaving behind the suspended array of resonant MoS2 nanoelectromechanical systems (NEMS). We then experimentally demonstrate a consistent upward frequency tuning up to 160% and downward quality (Q) factor shift as DC gate voltage (VGS) increases. The measured resonance frequencies and Q factors among different devices show smaller variations compared with previous reports. The new transfer technique enables consistent and high-quality 2D NEMS resonator arrays, and paves the way towards scalable and low-cost production of 2D NEMS resonators for on-chip sensing, radio-frequency (RF) signal processing, and computing.