Symmetry-Breaking-Induced Frequency Combs in Graphene Resonators

Nonlinearities are inherent to the dynamics of two-dimensional materials. Phenomena-like intermodal coupling already arise at amplitudes of only a few nanometers, and a range of unexplored effects still awaits to be harnessed. Here, we demonstrate a route for generating mechanical frequency combs in graphene resonators undergoing symmetry...

Sensitive Transfer-Free Wafer-Scale Graphene Microphones

During the past decades micro-electromechanical microphones have largely taken over the market for portable devices, being produced in volumes of billions yearly. Because performance of current devices is near the physical limits, further miniaturization and improvement of microphones for mobile devices poses a major challenge that requires...

Squeeze-Film Effect on Atomically Thin Resonators in the High-Pressure Limit

The resonance frequency of membranes depends on the gas pressure due to the squeeze-film effect, induced by the compression of a thin gas film that is trapped underneath the resonator by the high-frequency motion. This effect is particularly large in low-mass graphene membranes, which makes them promising candidates for pressure-sensing...

Multi-layer graphene Pirani pressure sensors

The operating principle of Pirani pressure sensors is based on the pressure dependence of a suspended strip's electrical conductivity, caused by the thermal conductance of the surrounding gas which changes the Joule heating of the strip. To realize such sensors, not only materials with high temperature dependent electrical conductivity are...

Nonequilibrium thermodynamics of acoustic phonons in suspended graphene

Recent theory has predicted large temperature differences between the in-plane [longitudinal (LA) and transverse (TA)] and out-of-plane [flexural (ZA)] acoustic phonon baths in locally heated suspended graphene. To verify these predictions, and their implications for understanding the nonequilibrium thermodynamics of two-dimensional (2D)...

High-frequency stochastic switching of graphene resonators near room temperature

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...

Sealing graphene nanodrums

Despite theoretical predictions that graphene should be impermeable to all gases, practical experiments on sealed graphene nanodrums show small leak rates. Thus far, the exact mechanism for this permeation has remained unclear, because different potential leakage pathways have not been studied separately. Here, we demonstrate a sealing method...

Graphene gas pumps

We report on the development of a pneumatically coupled graphene membrane system, comprising of two circular cavities connected by a narrow trench. Both cavities and the trench are covered by a thin few-layer graphene membrane to form a sealed dumbbell-shaped chamber. Local electrodes at the bottom of each cavity allow for actuation of each...

Colorimetry Technique for Scalable Characterization of Suspended Graphene

Previous statistical studies on the mechanical properties of chemical-vapor-deposited (CVD) suspended graphene membranes have been performed by means of measuring individual devices or with techniques that affect the material. Here, we present a colorimetry technique as a parallel, noninvasive, and affordable way of characterizing suspended...