CO Gas Sensing Properties of Chemically Deposited ZnO: Al Thin Films

In this research work, the structural and optical properties of undoped and Al doped ZnO thin films are being reported. The nanocrystalline ZnO thin films were deposited on glass substrate by chemical bath deposition technique using zinc acetate (AR), triethanolamine (AR), sodium hydroxide (AR) as the source materials and aluminum nitrate as source of the dopant. The structural characterization was done by XRD (X-ray diffraction). The crystallite size was found to decrease on doping of Al. SEM (Scanning Electron Microscope) was employed to examine the surface morphology of thin films and formation of ZnO nanorod was observed. The optical band gap of thin films was studied by UV-Visible spectroscopy. The band gap energy was found to vary from 3.84 eV to 4.0 eV. The electrical and CO gas sensing properties of thin films were also investigated. For application purpose, the quick response of chemically synthesized ZnO thin films to CO gas was observed and the fast recovery in absence of CO gas was also observed.