Title: Atomic Layer Semiconductor 2D Nanoelectromechanical Systems (NEMS)

 

Abstract: Electrical Engineering, Case School of Engineering, Case Western Reserve University

Atomically thin semiconducting crystals derived from new classes of layered materials have rapidly emerged to enable two-dimensional (2D) nanostructures with unusual electronic, optical, mechanical, and thermal properties.  While graphene has been the forerunner and hallmark of 2D crystals, newly emerged 2D semiconductors offer intriguing, beyond-graphene, attributes.  The sizable and tunable bandgaps of compound and single-element 2D semiconductors offer attractive perspectives for strong multiphysics coupling and efficient transduction across various signal domains.  In this presentation, I will describe my research group’s latest efforts on investigating how mechanically active atomic layer semiconductors and their heterostructures interact with optical and electronic interrogations, and on engineering such structures into new ultrasensitive transducers and signal processing building blocks.  Using single- and few-layer transition metal di-chalcogenide (TMDC) crystals, we demonstrate multimode resonant 2D nanoelectromechanical systems (NEMS) with extraordinary electrical tunability.  We have also found remarkably broad dynamic range (DR~70 to 100dB) in these 2D NEMS, via deterministic measurement of device intrinsic noise floor and onset of nonlinearity.  I will describe spatial mapping and visualization of mode shapes and Brownian motion in these 2D multimode resonators, along with their applications in resolving intrinsic anisotropy and structural asymmetry.  I shall then discuss emerging device applications, from classical information processing technologies to 2D NEMS operating in their quantum regime.  

Short Bio:  Philip Feng is an Associate Professor in EECS at the Case School of Engineering, Case Western Reserve University (CWRU). His group’s research is primarily focused on emerging semiconductor devices and integrated microsystems. He received his Ph.D. in EE from Caltech (2007). His recent awards include NSF CAREER Award, 4 Best Paper Awards (with his advisees, at IEEE and American Vacuum Society conferences), and a university-wide T. Keith Glennan Fellowship. He is also the recipient of the Case School of Engineering Graduate Teaching Award (2014) and the Case School of Engineering Research Award (2015). He was one of the 81 young engineers selected to participate in the National Academy of Engineering (NAE) 2013 U.S. Frontier of Engineering (USFOE) Symposium. Subsequently, he was selected to receive the NAE Grainger Foundation Frontiers of Engineering (FOE) Award in 2014. He was nominated for the John S. Diekhoff Award (2016) for distinguished graduate student mentoring, and for the Bruce Jackson Award (2016) for excellent undergraduate mentoring. Feng has >100 peer-reviewed publications and 6 patents. A Senior Member of IEEE, he has served on the Technical Program Committees (TPC) and as Track/Session Chairs for IEEE IEDM, IEEE MEMS, Transducers, IEEE IFCS, IEEE SENSORS, IEEE NANO, etc.  

Related References:  

[1] Yang, Lee, Feng, et al., “Tuning Optical Signature of Single- and Few-Layer…” Nano Lett. 17, 4568-4575 (2017).  

[2] Wang, Jia, Feng, et al., “Resolving and Tuning Mechanical Anisotropy…”, Nano Lett. 16, 5394-5400 (2016).  

[3] Lee, Wang, Feng, et al., “High Frequency MoS2 Nanomechanical Resonators”, ACS Nano 7, 6086-6091 (2013).  

[4] Wang, Lee, Feng, “Spatial Mapping of Multimode Brownian Motions…”, Nature Communications 5, 5158 (2014).  

[5] Yang, Islam, Feng, “Electromechanical Coupling & Design Considerations in Single-Layer…”, Nanoscale 7, 19921-29 (2015).  

[6] Yang, Zheng, Feng, et al., “Multilayer MoS2 Transistors Enabled by a Facile Dry-Transfer Technique…”, Journal of Vacuum Science & Technology B 32, 061203 (2014). (Cover Article, Editor’s Pick, ‘Most Read’ of the Month)

[7] Wang, Jia, Feng, et al., “Black Phosphorus Nanoelectromechanical Resonators…”, Nanoscale 7, 877-884 (2015).  

[8] Yang, Wang, Feng, et al., “Electrical Breakdown of MoS2 Transistors…”, Nanoscale 6, 12383-12390 (2014).  

[9] Wang, Lee, Feng, et al., “Embracing Structural Nonidealities in 2D…”, Scientific Reports 4, 3919 (2014).