A Review of Acoustic Devices Based on Suspended 2D Materials and Their Composites

Abstract

Acoustic devices play an increasingly important role in modern society for information technology and intelligent systems, and recently significant progress has been made in the development of communication, sensing, and energy transduction applications. However, conventional material systems, such as polymers, metals and silicon, show limitations to fulfill the evolving requirements for high‐performance acoustic devices of small size, low power consumption, and multifunctional capabilities. 2D materials hold the promise in overcoming the development bottleneck of acoustic devices aforementioned, given their atomic‐thin thickness, extensive surface area, superior physical properties, and remarkable layer‐stacking tunability. By suspending the 2D materials, mechanical and thermal disruption from substrate will be eliminated, which will enable the development of new classes of acoustic devices with unprecedented sensitivity and accuracy. In this review, the recent progress of acoustic devices based on suspended 2D materials and their composites, especially applications in the audio frequency, static pressure, and ultrasonic frequency range, is briefly summarized, emphasizing the advantageous properties of suspended 2D materials and related outstanding device performance. Together with the development of 2D membrane synthesis, transfer, as well as microelectromechanical fabrication process, suspended 2D materials will shed light on the next‐generation high‐performance acoustic devices.

Tuning instability in suspended monolayer 2D materials

“…That means the 2D planar structure will undergo out-of-plane deformations, such as rippling, buckling, wrinkling, or even creasing, when triggered by geometrical constraints 4 , which have significant influences on the mechanical 5 , 6 , electrical 7 , and thermal 8 properties of 2D materials. Their mechanical stability, therefore, becomes especially important in those device applications including suspended 2D-based Micro/Nanoelectromechanical systems (M/NEMS) 9 , resonator/oscillator 10 , kirigami/origami 11 , electrodes 12 and nanochannels 13 – 15 . Recently, the wrinkles induced by instability in monolayer graphene were demonstrated to accelerate proton transport 16 , which has renewed demands in tuning of instability morphology of suspended 2D materials.…”