Ultra Small Single Walled Carbon Nanotube Pressure Sensors

This paper reports on the fabrication and characterization of ultra small pressure sensors with individual single-walled carbon nanotube (SWNT) field effect transistors (CNFETs) as strain gauges. The smallest piezoresistive pressure sensor with a membrane diameter of d~40 mum is fabricated and characterized. This miniaturization is made possible due to the nanoscaled size, electronic properties, and high piezoresistive gauge factors (GF) of SWNTs and is currently limited by the membrane fabrication capabilities using a 200 mum thick Si wafer. In summary the sensor performance is: gauge factor: ~450 to 700 (strain dependent), sensitivity: -54 pA/mbar (V_ds=200 mV), resolution: 15mbar, power consumption: ~100nW.