In- and Sb-doped tin oxide nanocrystalline films for selective gas sensing

Highly sensitive, Si-integrated gas sensors based on undoped, In- and Sb-doped nanocrystalline SnO2-films, have been fabricated by spray pyrolysis. We have found that the In-doped gas sensors show significantly improved sensitivity for CH4 detection and low sensitivity for H-2 detection, while Sb-doped sensors exhibit high sensitivity towards H-2 and comparatively low sensitivity for CH4 detection. The results demonstrate that a device implementing both a In-doped SnO2 sensor as well as a Sb-doped sensor should be capable for well defined discrimination of CH4 and H-2-gases when mixed to synthetic air as background gas. This indicates that proper doping of SnO2-films is a powerful strategy for the future realization of Si-integrated multi-gas sensor systems. (C) 2009 Elsevier B.V. All rights reserved.