The paper describes experiments with graphene membrane based pressure sensors with very high normalized sensitivity. In addition, we report an intrinsic graphene gauge factor of 2.9. The observed piezoresistive effect is independent of crystallographic orientation, in line with theoretical calculations. This is an important result in view of potential applications in sensors and actuators and promises significantly smaller sensors with improved sensitivity.
Monolayer graphene exhibits exceptional electronic and mechanical properties, making it a very promising material for nanoelectromechanical devices. Here, The researchers conclusively demonstrate the piezoresistive effect in graphene in a nanoelectromechanical membrane configuration that provides direct electrical readout of pressure to strain transduction. This makes it highly relevant for an important class of nano-electromechanical systems (NEMS) transducers.
This demonstration is consistent with simulations and previously reported gauge factors and simulation values. The membrane in this experiment acts as a strain gauge independent of crystallographic orientation and allows for aggressive size scalability. When compared with conventional pressure sensors, the sensors have orders of magnitude higher sensitivity per unit area.
The research was supported through three ERC Grants (OSIRIS, No. 228229, M&Mís, No. 277879 and InteGraDe, No. 307311) as well as the German Research Foundation (DFG, LE 2440/1-1) and the Italian MIUR through the Cooperlink project (CII11AVUBF).