Nitrogen dioxide and Ammonia Gas Sensing by Tungsten Trioxide Film
Presented by Mr. Malcolm GOVENDER on 8 Jul 2014 from 14:20 to 14:40
Type: Oral Presentation
Track: Track A - Division for Physics of Condensed Matter and Materials
Tungsten oxide film was reactively-sputtered on alumina substrate with Pt-contacts from a pure W target and argon/oxygen-plasma. The synthesized and annealed tungsten oxide was characterized with XRD, XPS, Raman spectroscopy, UV/Vis spectroscopy and Resistance as a function of Temperature, and found to be stoichiometric triclinic phase tungsten trioxide. The pure film was used to sense ppm concentrations of nitrogen dioxide and ammonia at room-temperature and 100<sup>o</sup>C. At 100<sup>o</sup>C, The sensitivity of the film towards nitrogen dioxide increased, and decreased significantly towards ammonia. This was due to tungsten trioxide being an n-type metal-oxide semiconductor which preferred the reaction with the oxidizing gas over the reducing gas.
Dr. Bonex W. Mwakikunga BMwakikunga@csir.co.za