Preparation of nanocrystalline nickel oxide thin films by sol-gel process for hydrogen sensor applications

Preparation of nanocrystalline NiO thin films by sol-gel method and their hydrogen (H-2) sensing properties were investigated. The thin films of NiO were successfully deposited on the glass and SiO2/Si substrate by a sol-gel coating method. The films were characterized for crystallinity, electrical properties, surface topography and optical properties as a function of calcination temperature and substrate material. It was found that the films produced by this method were polycrystalline and phase pure NiO. The H-2 gas sensitivity of these films was studied as a function of H-2 concentration and calcination temperature. The results indicated that the sol-gel derived NiO films could be used for the fabrication of H-2 gas sensors to monitor low concentration of H-2 in air quantitatively at low temperature range (<200 degrees C). (C) 2012 Elsevier B.V. All rights reserved.