High-Frequency Stochastic Switching of Graphene Resonators Near Room Temperature

Abstract

Stochastic switching between the two bistable states of a strongly driven mechanical resonator enables detection of weak signals based on probability distributions, in a manner that mimics biological systems. However, conventional silicon resonators at the microscale require a large amount of fluctuation power to achieve a switching rate in the order of a few hertz. Here, we employ graphene membrane resonators of atomic thickness to achieve a stochastic switching rate of 4.1 kHz, which is 100 times faster than current state-of-the-art. The (effective) temperature of the fluctuations is approximately 400 K, which is 3000 times lower than the state-of-the-art. This shows that these membranes are potentially useful to transduce weak signals in the audible frequency domain. Furthermore, we perform numerical simulations to understand the transition dynamics of the resonator and use analytical expressions to investigate the relevant scaling parameters that allow high-frequency, low-temperature stochastic switching to be achieved in mechanical resonators.

Dynamics of 2D material membranes

“…The noise might then help to amplify weak signals via a phenomenon called stochastic resonance [145]. An advantage of graphene nanodrums is that they can achieve stochastic switching rates as high as a few kHz near room temperature [38], hundred times faster than in conventional silicon resonators [146] at effective temperatures that are 3000 times lower, which could prove beneficial for enabling fast sensors based on stochastic resonance.…”

“…This makes 2D material membranes excellent probes for studying a variety of nonlinear dynamic effects, including mode-coupling [27][28][29][30], high resonancefrequency-tunability [14,31], parametric [32,33] and internal resonances [34,35]. Second, their mass is extremely small, which increases resonance frequencies yielding high sensitivity in sensing applications [10,23,[36][37][38]. Third, their high surfaceto-volume-ratio makes them very sensitive to their environment.…”

The Recent Progress of MEMS/NEMS Resonators

“…Graphene has low mass and low stiffness with superior mechanical properties [ 98 ]. As a membrane resonator, it is an atomic-level ultra-thin and super-strong material that can resonate at megahertz to achieve high stochastic switching rates [ 26 ]. At the same time, its high-frequency resonance can be tuned by applying voltage.…”

“…Since the switching rate follows Kramer’s law and increases as the effective temperature increases, using a VNA to drive the membrane at a fixed frequency and using an arbitrary waveform generator (AWG) to add random fluctuations to the resonator artificially will increase the effective temperature, and increasing the fluctuating power will increase the switching rate. A switching rate of up to 4.1 kHz is obtained at room temperature, which is more than 100 times higher than that of existing mechanical resonators [ 26 ]. In order to detect the in-plane stress of multilayer graphene in real-time by measuring the resonant frequency of the resonator, Robinson et al fabricated a nanomechanical drum resonator with a diameter of .…”

“…The microdisk and the pedestal can be manufactured by etching using the same material, or microdisks of different materials can be grown on the pedestal. Drum resonators are mostly membrane structures, such as a single-layer graphene membrane with low mass and low rigidity [ 26 ] and silicon nitride membranes with low stress [ 23 ]. The ring structure resonator can be used as gyroscopes, supported by a central anchor, and equidistant rings are nested with each other by spokes, and different resonance modes appear under the excitation of electrodes [ 27 ].…”