Large Scale Graphene for Piezoresistive Pressure Sensor Applications |
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Chemical vapor deposition (CVD) is a promising method to achieve large scale and high quality graphene films. We have reported the observation of electrons ballistically transport in CVD graphene [1]. Our work on the thermal activated bimorph effect of CVD graphene has shown that the deflection of actuator can be monitored by measuring the electrical resistance change of graphene. This method has a very high sensitivity and a high efficiency to miniaturize. However, the absence of a robust integration method for graphene films and the lack of a detailed understanding of the electro-mechanical behavior constitute the main obstacles for using this material. We will discuss our new developed scalable integration method by patterning graphene meander resistor onto more robust silicon nitride film as a pressure sensor [3]. By varying the applied differential pressure, we extract piezoresistive dependency of graphene films, which can be utilized for ultra-sensitive metrological applications.We present a pressure sensor based on the piezoresistive effect of graphene. The sensor is a 100 nm thick, 280 μm wide square silicon nitride membrane with graphene meander patterns located on the maximum strain area. The multilayer, polycrystalline graphene was obtained by chemical vapor deposition. Strain in graphene was generated by applying differential pressure across the membrane. Finite element simulation was used to analyze the strain distribution. By performing electromechanical measurements, we obtained a gauge factor of ∼1.6 for graphene and a dynamic range from 0 mbar to 700 mbar for the pressure sensor. | |
Shou-En Zhu, Delft University of Technology |