Self-Sealing Complex Oxide Resonators

Although 2D materials hold great potential for next-generation pressure sensors, recent studies revealed that gases permeate along the membrane-surface interface, necessitating additional sealing procedures. In this work, we demonstrate the use of free-standing complex oxides as self-sealing membranes that allow the reference cavity beneath...

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...

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...

Suspended graphene beams with tunable gap for squeeze-film pressure sensing

We present suspended graphene pressure sensors fabricated using an innovative surface micro-machining process. The great advantage of this process is that the molybdenum (Mo) catalyst layer for multi-layer graphene chemical vapor deposition (CVD) is also used as a sacrificial layer to suspend the graphene. This method allows for accurate control...

Static capacitive pressure sensing using a single graphene drumg

To realize nanomechanical graphene-based pressure sensors, it is beneficial to have a method to electrically readout the static displacement of a suspended graphene membrane. Capacitive readout, typical in micro-electromechanical systems, gets increasingly challenging as one starts shrinking the dimensions of these devices because the expected...

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...

Graphene gas osmometers

We show that graphene membranes that separate two gases at identical pressure are deflected by osmotic pressure. The osmotic pressure is a consequence of differences in gas permeation rates into a few-layer graphene enclosed cavity. The deflection of the membrane is detected by measuring the tension-induced resonance frequency with an...