Improvement of recovery time of nanostructured tin dioxide-based thick film gas sensors through surface modification

Along with high sensitivity towards detecting gases, the response and recovery times of semiconductor gas sensors are of paramount importance for practical applications. In most of the cases, the recovery time is larger than the response time. Incidentally, water vapour present in the ambience is chemisorbed on the semiconductor oxide surface and the water molecules dissociate into hydroxyl species, which act as electron donors. In the present study on tin dioxide-based methane sensor, we find that if the interference of adsorbed moisture can be reduced by surface treatment with a dilute thiourea solution, the recovery time and stability of the sensor improve, which make them suitable for practical applications. (c) 2007 Elsevier B.V. All rights reserved.