Invited Speaker

Prof. Rui Yang

Shanghai Jiao Tong University

E-mail: rui.yang@sjtu.edu.cn

Title:

2D Nanoelectromechanical Resonators with Thermal Treatment and Their Surface Effect

Profile:

Rui Yang is currently a Professor in Shanghai Jiao Tong University, Shanghai, China. He obtained the Ph.D. degree from Case Western Reserve University in 2016. From 2016 to 2018, he was a postdoctoral scholar at Stanford University, working with Prof. Philip Wong and Jonathan Fan. He joined Shanghai Jiao Tong University in August 2018. His main research directions include 2D NEMS resonators for sensing and computing, and RRAMs and ferroelectric memories for in-memory computing and neuromorphic computing. He has published more than 50 papers as first author/corresponding author in high-quality journals and conferences such as Nature Electronics, Nature Communications, and IEDM. He is the Associate Editor of Microsystems & Nanoengineering, Associate Editor of IEEE Transactions on Electron Devices, Reviews Editor of Nanotechnology, and Editorial Board Member of Chip. He has obtained a number of awards such as “2DM Emerging Young Scientist Award” from 2024 International Forum on Graphene in Shenzhen, “Excellent Young Scientist Award” from the 3rd National Conference on Electronic Information Materials and Devices, “Scientific Innovation Award” from the 2nd Symposium on Smart Materials and Optoelectronic Devices, “Shanghai Rising Star Program”, “Shanghai Sailing Program”, “2019 Ten Junior Faculty on Cutting-Edge Technology in China”, “Forbes China 30 Under 30 Award” in Science Category, and “Young Scientist Award in Microsystems & Nanoengineering Summit 2019”.

Abstract:

Ultra-thin 2D materials such as MoS2 have excellent mechanical properties, such as ultra-low weight, high Young's modulus, and high strain limit, and only require picowatt (10-12 W) range of power to maintain strong and stable resonance, making them ideal for 2D NEMS resonators.  However, the quality (Q) factor, electrical signal transmission characteristics, measurement and tuning methods of 2D NEMS resonators have not been fully studied and optimized, thus it is difficult to fully leverage the advantages of these NEMS resonators.  In addition, while mechanical resonators have been used in sensors and radio-frequency (RF) signal processing previously, their memory and computing mechanisms are still not clear.  To integrate 2D devices, the large-scale growth and transfer of 2D materials is important, but the fabrication of large-scale suspended 2D NEMS arrays is still challenging. To solve the problems, we study the thermal treatment and surface effects on damping and Q factor.  In NEMS resonators, a larger Q indicates less energy dissipation, which leads to stronger oscillations at resonance under the same external excitation, and sharper resonant peaks with better frequency selectivity.  We have achieved strain tuning of Q in 2D MoS2 NEMS resonators with different boundary conditions, established a model about how tensile strain improves the Q, and experimentally measured strain tuning of Q by up to ΔQ/Q = 448%.  This provides a new way to develop ultra-low-power, low-loss, and tunable devices for on-chip information processing.  In addition, we discover the surface nonideality effect on Q factor, and optimize the Q factor in 2D NEMS resonators.  Moreover, we fabricate large-scale arrays of 2D NEMS resonators based on thermal treatment, and develop NEMS memories based on thermal hysteresis effect.  The results are important for on-chip sensing and computing based on 2D NEMS resonators.