Graphene-Based Nanoelectromechanical Periodic Array with Tunable Frequency

Abstract

Phononic crystals (PnCs) have attracted much attention due to their great potential for dissipation engineering and propagation manipulation of phonons. Notably, the excellent electrical and mechanical properties of graphene make it a promising material for nanoelectromechanical resonators. Transferring a graphene flake to a prepatterned periodic mechanical structure enables the realization of a PnC with on-chip scale. Here, we demonstrate a nanoelectromechanical periodic array by anchoring a graphene membrane to a 9 × 9 array of standing nanopillars. The device exhibits a quasi-continuous frequency spectrum with resonance modes distributed from ∼120 MHz to ∼980 MHz. Moreover, the resonant frequencies of these modes can be electrically tuned by varying the voltage applied to the gate electrode sitting underneath. Simulations suggest that the observed band-like spectrum provides an experimental evidence for PnC formation. Our architecture has large fabrication flexibility, offering a promising platform for investigations on PnCs with electrical accessibility and tunability.

Nanomechanical Resonators: Toward Atomic Scale

“…222,223 In one example with graphene transferred onto an array of nanopillars, measurements suggest the formation of a phononic crystal with a quasi-continuous frequency spectrum. 268 In another example, phononic crystal waveguides in engineered h-BN In addition to phononic structures, low-dimensional NEMS resonators can also be coupled to photonic and optomechanical devices. In one example, a graphene resonator coupled to an on-chip waveguide was used to locally detect the hybridization between the propagating optical modes, by sensing changes in the optical gradient force (a kind of radiation pressure) produced by the light which affects the vibration amplitude.…”

A Review on Graphene-Based Nano-Electromechanical Resonators: Fabrication, Performance, and Applications

“…The feasibility of phononic crystals based on graphene electromechanical resonators is studied theoretically and experimentally [89,90]. In the experiment, Zhang et al fabricated a graphene-based nano-electromechanical periodic array with a quasi-continuous spec-trum [91]. The spectrum had a range of hundreds MHz and was regulated by gate voltage.…”

Coherent Phononics of van der Waals Layers on Nanogratings

“…Also, high-frequency immobile hybrid flexural phonon modes are generated due to coupling of phonons above the grooves and ridges of the nanograting. This new type of 2D periodic phononic nanoobject, a flexural phononic crystal, opens up exciting directions for exploitation of phonon hybridization effects in vdW materials at frequencies more than 1 order of magnitude higher than recently studied vdW based phononic crystals. , …”

“…This new type of 2D periodic phononic nanoobject, a flexural phononic crystal, opens up exciting directions for exploitation of phonon hybridization effects in vdW materials at frequencies more than 1 order of magnitude higher than recently studied vdW based phononic crystals. 11,12 As discussed below, our research goes beyond the investigation of phonon modes in free-standing vdW layers, 13 which are well-known to consist of a number of symmetric (S) and antisymmetric (A) elastic Lamb waves with frequency ω(q), where q is the in-plane wavevector. 14 The two upper images in Figure 1b illustrate the displacement of atoms in the lowest antisymmetric (A0) and symmetric (S0) Lamb modes.…”