Atomic Layer Semiconductor 2D Nanoelectromechanical Systems (NEMS)

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.