Graphene "microdrums" on a freestanding perforated thin membrane for high sensitivity MEMS pressure sensors

• Published in: Nanoscale Vol. 8; no. 14; pp. 7663 - 7671
• Main Authors: Wang, Qiugu, Hong, Wei, Dong, Liang
• Format: Journal Article
• Language: English
• Published: England 14.04.2016
• Subjects: Graphene; Linearity; Membranes; Microelectromechanical systems; Pressure sensors; Sensor arrays; Sensors; Strain
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c5nr09274d

We present a microelectromechanical system (MEMS) graphene-based pressure sensor realized by transferring a large area, few-layered graphene on a suspended silicon nitride thin membrane perforated by a periodic array of micro-through-holes. Each through-hole is covered by a circular drum-like graphene layer, namely a graphene "microdrum". The uniqueness of the sensor design is the fact that introducing the through-hole arrays into the supporting nitride membrane allows generating an increased strain in the graphene membrane over the through-hole array by local deformations of the holes under an applied differential pressure. Further reasons contributing to the increased strain in the devised sensitive membrane include larger deflection of the membrane than that of its imperforated counterpart membrane, and direct bulging of the graphene microdrum under an applied pressure. Electromechanical measurements show a gauge factor of 4.4 for the graphene membrane and a sensitivity of 2.8 × 10 −5 mbar −1 for the pressure sensor with a good linearity over a wide pressure range. The present sensor outperforms most existing MEMS-based small footprint pressure sensors using graphene, silicon, and carbon nanotubes as sensitive materials, due to the high sensitivity. An ultrahigh-sensitivity graphene-based MEMS pressure sensor is developed by transferring a few-layered graphene membrane on a suspended silicon nitride membrane perforated by a periodic array of micro-through-holes.