Sensitivity Enhancement of Piezoresistive Pressure Sensor using Carbon Nanotube as a Piezoresistor

Piezoresistive pressure sensors works on the principle of piezoresistive effect of a material to detect strain when pressure is applied. To enhance the sensitivity and linearity of the device, generally the piezoresistive materials are connected in the form of a Wheatstone bridge circuit. For the design of a proposed model, silicon material is used for diaphragm and gold for connectors and carbon nanotubes (CNT) for piezoresistors, since CNTs have a high gauge factor. The proposed pressure sensor is designed and simulated using Comsol and Coventorware, and analyzed with respect to different parameters such as maximum displacement of the membrane, change in the electrical resistance of piezoresistors, output voltage and sensitivity of the sensor. The sensitivity of the proposed sensor is 0.145mV/V/kPa.