Effect of Dispersal of Pd Nanocatalysts on H_2 Sensing Response of SnO_2 Thin Film Based Gas Sensor

摘要

SnO_2 based sensor structures prepared by rf magnetron sputtering technique have been studied for detecting H_2 gas. Pd catalyst was integrated onto the SnO_2 thin film in the form of clusters and nano-particles to obtain enhanced sensing response characteristics. The prepared sensor structures have been studied over a temperature range of 50-250°C for sensing response towards 500 ppm H_2 gas. The sensor with Pd catalyst dispersed in the form of nanoparticles was found to exhibit an enhanced sensing response of 1.9×10~3 at a relatively low operating temperature of 150°C with a fast response time of 2 s and recovery time of 65 s towards 500 ppm H_2 gas. The origin of enhanced sensing response is identified in the light of the enhanced spill over of H_2 gas molecules on the uncovered surface of SnO_2 thin film.