Fabrication of highly sensitive field emission based pressure sensor, using CNTs grown on micro-machined substrate

Carbon nanotubes have been used as cold cathode emitter in the fabrication of a sensitive field emission pressure sensor. Vertically aligned carbon nanotubes were grown using the plasma-enhanced chemical vapor deposition (PECVD) on a micro-machined silicon substrate. A silicon membrane was used as the flexible anode against the fabricated CNT-based cathode. A 2-mu m thick SiO2 layer has been applied as the anode-cathode spacer and the output results have been compared with a similar sensor with 120 mu m spacer. Results show that the sensitivity and the output emission current of the fabricated sensor have been highly improved by decreasing the anode-cathode spacing. Measurements show an ultra-high sensitivity of about 100-970 mu A/kPa which is higher than the similar pressure sensors. Low working voltage and high thermal stability of the fabricated sensor are among the other advantages of the presented sensor (C) 2013 Elsevier B.V. All rights reserved.