Sol-Gel Prepared Single Wall Carbon Nanotube SnO_2 Thin Film for Micromachined Gas Sensor

摘要

We report here a novel micromachined single wall carbon nanotube (SWNT)/tin dioxide (SnO_2) nano film gas sensor. A polymeric sol-gel process in combination with purified SWNT has been successfully developed in fabricating SWNT/SnO_2 thin film nanocomposite sensor on an alumina substrate. The test of the novel nanocomposite gas sensors has been conducted for hydrogen detection, in comparison with sol gel derived SnO_2 thin film. The test results show that SWNT has greatly improved the nano-SnO_2 thin film's gas sensing property, in terms of lower working temperature, greater sensitivity (a factor of 3), faster response time and recovery time, and less drift of resistance. The improved capabilities are credited to the large surface to volume ratio of gas sensing thin film with nano passes created by SWNT, and the distance between adjacent passages being less than electron depletion layer thickness is defined by SWNT. The fabrication process is compatible with IC industry thus it is cost effective for batch production.