AVS 53rd International Symposium
    Thin Film Tuesday Sessions
       Session TF-TuP

Paper TF-TuP25
Preparation and Photocatalytic Activity of CdS/TiO@subX@N@subY@ Heterojunctions

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Thin Film Poster Session
Presenter: K. Prabakar, University of Toyama, Japan
Authors: K. Prabakar, University of Toyama, Japan
T. Takahashi, University of Toyama, Japan
K. Takahashi, University of Toyama, Japan
T. Nezuka, University of Toyama, Japan
T. Nakashima, Kashiwa Chuo High School, Japan
Y. Kubota, University of Yokohama City, Japan
A. Fujishima, Kanagawa Academy of Science and Technology, Japan
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Currently TiO@sub2@ is the most popular semiconductor used in photocatalysis. However, TiO@sub2@ absorbs only a small fraction of solar light because of its wide band gap energy of 3.2 eV. To extend the light absorbing property of TiO@sub2@ and to enhance its photocatalytic efficiency is to dope TiO@sub2@ with nitrogen and also couple with narrow band gap semiconductors. In this coupled heterojunctions, an improvement of charge separation, increase in life time of the charge carriers and enhancement of the interfacial charge transfer efficiency could be achieved. CdS thin films were prepared by chemical bath deposition. Cadmium sulphate, thiourea and ammonium nitrate were used as precursor to deposit the CdS thin films. On the other hand, nitrogen doped TiO@sub2@ (TiO@subX@N@subY@) films are activated by visible light as well as ultraviolet radiation have been prepared by DC magnetron sputtering in an argon, oxygen and nitrogen atmosphere using titanium metal target. The band gap energy of CdS thin films was tailored between 2.1 to 2.5 eV. The substitutional nitrogen doping to TiO@sub2@ was found to be effective in decreasing the band gap of the films. The band gap energy of the as-deposited TiO@subX@N@subY@ thin films was found to be 2.8 eV. X-ray diffraction, scanning electron microscopy, atomic force microscopy and UV-VIS spectrometers were used to analyze the structural, surface morphology and optical properties of the prepared films respectively. The gaseous photocatalytic activity of CdS/TiO@subX@N@subY@ heterojunctions was studied on 2-propanol and methanol using a FTIR spectrophotometer. The photocatalytic efficiency greatly depends on the surface nature of the CdS films. The effect of preparation conditions, annealing temperature on the photocatalytic activity of CdS/TiO@subX@N@subY@ heterojunctions was studied and the results are discussed.