Hexagonal boron nitride nanomechanical resonators with spatially visualized motion

Journal Article · Mon Jul 31 04:00:00 UTC 2017 · Microsystems & Nanoengineering (Online)

DOI: https://doi.org/10.1038/micronano.2017.38 · OSTI ID:1425389

Zheng, Xu-Qian ^[1]; Lee, Jaesung ^[2]; Feng, Philip X. -L. ^[2]

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1. Case Western Reserve Univ., Cleveland, OH (United States); Case Western Reserve University
2. Case Western Reserve Univ., Cleveland, OH (United States)

Atomic layers of hexagonal boron nitride (h-BN) crystal are excellent candidates for structural materials as enabling ultrathin, two-dimensional (2D) nanoelectromechanical systems (NEMS) due to the outstanding mechanical properties and very wide bandgap (5.9 eV) of h-BN. In this work, we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies (from ~ 5 to ~ 70 MHz), and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices. First, we demonstrate a dry-transferred doubly clamped h-BN membrane with ~ 6.7 nm thickness, the thinnest h-BN resonator known to date. In addition, we fabricate circular drumhead h-BN resonators with thicknesses ranging from ~ 9 to 292 nm, from which we measure up to eight resonance modes in the range of ~ 18 to 35 MHz. Combining measurements and modeling of the rich multimode resonances, we resolve h-BN’s elastic behavior, including the transition from membrane to disk regime, with built-in tension ranging from 0.02 to 2 N m^-1. The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances. The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms, including anisotropic built-in tension and bulging, thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.

• Research Organization: Case Western Reserve Univ., Cleveland, OH (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: EE0006719
• OSTI ID: 1425389
• Journal Information: Microsystems & Nanoengineering (Online), Journal Name: Microsystems & Nanoengineering (Online) Vol. 3; ISSN 2055-7434
• Country of Publication: United States
• Language: English