Radio-Frequency Nanoelectromechanical Systems in Atomically-Thin Crystals

Nanoscience today enables exciting emergences of low-dimensional nanostructures and new materials with previously inaccessible properties. We explore these intriguing properties, coupled with mechanical degrees of freedom in designed and engineered nanostructures, to innovate new nanomachines and transducers, for sensing and information processing. In particular, nanoscale electromechanical systems (NEMS) operating in their resonant modes can be exquisitely sensitive to various processes. By engineering high-performance NEMS resonators in the radio frequency (RF) and microwave bands, especially those based on one-dimensional (1D) and two-dimensional (2D) nanostructures, we have demonstrated various ultrasensitive transducers. In this talk, I will focus on introducing 2D NEMS based on atomically-thin crystals. While graphene has been very well known as the hallmark of 2D crystals, other interesting 2D crystals with tunable bandgaps have emerged, such as layers from transition metal di-chalcogenides (TMDC). Atomically-thin structures derived from these materials possess a number of interesting electrical, optical, and mechanical properties, and are attractive for new nanodevices. I will describe our recent experiments on demonstrating various high-frequency graphene and MoS2 NEMS resonators. By performing sensitive optical and electronic measurements, in combination with modeling, we quantify the performance of these 2D NEMS, and evaluate their potential and ultimate limits in detecting strain, charge, and other quantities of interest. Challenges and advances in experimental techniques will also be discussed.

Philip Feng is currently an Assistant Professor in Electrical Engineering at Case School of Engineering, Case Western Reserve University. His research is primarily focused on nanoscale devices and systems. Prior to joining the faculty at Case, Feng was at the Kavli Nanoscience Institute, California Institute of Technology (Caltech), where he served as a Staff Scientist and a Co-Principal Investigator from 2007 to 2010. He received his Ph.D. from Caltech in 2007 for developing ultra high frequency (UHF) nanoelectromechanical systems (NEMS) with low-noise technologies for real-time single-molecule sensing, under the supervision of Prof. Michael Roukes. His recent awards include 1 Best Paper Award (with his advisee, at IEEE NEMS 2013) and 4 times of Best Paper Finalists, a T. Keith Glennan Fellowship (2012), an Innovative Incentive Award (2011). Feng was one of the 81 young engineers selected to participate in the National Academy of Engineering (NAE)'s 2013 U.S. Frontier of Engineering Symposium. He received the NAE's Grainger Foundation Frontiers of Engineering Award in 2014. He has been serving on the Technical Committees for IEEE IEDM, Transducers, IEEE International Frequency Control Symposium, IEEE NANO, and other IEEE conferences; he is serving as the MEMS/NEMS Technical Program Chair for the 61st AVS International Symposium (Baltimore, Nov. 2014).