Improved crystalline structure and H(2)S sensing performance of CuO-Au-SnO(2) thin film using SiO(2) additive concentration

Abstract

In situ SiO(2)-doped SnO(2) thin films were successfully prepared by liquid phase deposition. The influence of SiO(2) additive as an inhibitor on the surface morphology and the grain size for the thin film has been investigated. These results show that the morphology of SnO(2) film changes significantly by increasing the concentration of H(2)SiF(6) solution which decreases the grain size of SnO(2). The stoichiometric analysis of Si content in the SnO(2) film prepared from various Si/Sn molar ratios has also been estimated. For the sensing performance of H(2)S gas, the SiO(2)-doped Cu-Au-SnO(2) sensor presents better sensitivity to H(2)S gas compared with Cu-Au-SnO(2) sensor due to the fact that the distribution of SiO(2) particles in grain boundaries of nano-crystallines SnO(2) inhibited the grain growth (<6 nm) and formed a porous film. By increasing the Si/Sn molar ratio, the SiO(2)-doped Cu-Au-SnO(2) gas sensors (Si/Sn=0.5) exhibit a good sensitivity (S=67), a short response time (t(90%)<3 s) and a good gas concentration characteristic (alpha=0.6074). Consequently, the improvement of the nano-crystalline structures and high sensitivity for sensing films can be achieved by introducing SiO(2) additive into the SnO(2) film prepared by LPD method. (C) 2010 Elsevier B.V. All rights reserved.