NO2 sensing properties of WO3 varistor-type gas sensor

NO2 sensing properties of pure WO3 ceramics based on the gas sensitive nonlinear current-voltage (I-V) characteristics have been investigated Experimental results show that WO3 ceramics exhibit nonlinear I-V characteristics and breakdown voltage shift to a high electric field upon exposure to NO2 thus exhibiting NO2 sensitivity and the operating temperatures and voltages are relatively lower than the previous reported varistor-type gas sensors The mechanism of gas sensitive nonlinear I-V characteristics has been explained by the alternations of the potential barriers at the grain boundaries The present results demonstrate that WO3 can be used as a new varistor-type gas sensor material (C) 2010 Elsevier B V All rights reserved