Monolayer graphene exhibits exceptional electronic and mechanical properties, making it a very promising material for nanoelectromechanical devices. Here, we 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 nanoelectromechanical system (NEMS) transducers. This demonstration is consistent with our simulations and previously reported gauge factors and simulation values. The membrane in our 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.
Graphene
membranes act as highly sensitive transducers in nanoelectromechanical
devices due to their ultimate thinness. Previously, the piezoresistive
effect has been experimentally verified in graphene using uniaxial
strain in graphene. Here, we report experimental and theoretical data
on the uni- and biaxial piezoresistive properties of suspended graphene
membranes applied to piezoresistive pressure sensors. A detailed model
that utilizes a linearized Boltzman transport equation describes accurately
the charge-carrier density and mobility in strained graphene and,
hence, the gauge factor. The gauge factor is found to be practically
independent of the doping concentration and crystallographic orientation
of the graphene films. These investigations provide deeper insight
into the piezoresistive behavior of graphene membranes.
Abstract-This paper reports on novel electrostatically actuated dc-to-RF metal-contact microelectromechanical systems (MEMS) switches, featuring a minimum transmission line discontinuity since the whole switch mechanism is completely embedded inside the signal line of a low-loss 3-D micromachined coplanar waveguide. Furthermore, the switches are based on a multistable interlocking mechanism resulting in static zero-power consumption, i.e., both the onstate and the offstate are maintained without applying external actuation energy. Additionally, the switches provide with active opening capability, potentially improving the switch reliability, and enabling the usage of soft low-resistivity contact materials.
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