ZnO modified high aspect ratio carbon electrodes for hydrogen sensing applications

Abstract

Design, fabrication, and testing results of a hydrogen gas sensor based on a surface modified high density and high aspect ratio 3-D carbon post microarray are described in this paper. After the conversion of photoresist patterns into carbon electrodes, the increased surface was conformally coated with a metal oxide semiconductor film by atomic layer deposition (ALD). A maximum sensitivity as high as 100 (R air/R hydrogen) has been observed in the fabricated sensor even in the presence of moisture at low temperature. A fast initial response (90% resistance drop in 30 sec at 3000 ppm hydrogen) of the sensor could be utilized for early leak detection. The methodology of surface modification as well as the test result shows good promise for various chemical sensing devices based on the proposed strategy. © 2011 Published by Elsevier Ltd.