Speaker
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?
No
Level for award<br> (Hons, MSc, <br> PhD)?
PhD
Main supervisor (name and email)<br>and his / her institution
Bonex W. Mwakikunga, BMwakikunga@csir.co.za
CSIR-NCNSM
Abstract content <br> (Max 300 words)
Tungsten trioxide film was RF-sputtered onto alumina substrates. SEM studies over the sample area (1 cm2) showed uniform topology while FIB cross-sectioning showed the thickness to vary between 0.75-1.50 µm and this variation stems from the alumina roughness. The measured film resistance using a two-probe setup was found to be 5 kΩ at room temperature, and decreased to 2 kΩ at 300oC which is expected for n-type semiconducting materials. Raman spectroscopy of the films showed Raman shifts at approximately 267 cm-1, 700 cm-1 and 800 cm-1 which are indicative of tungsten trioxide. The films were used to sense ppm concentrations of NO2 and NH3 gas, and it was found that the film gave best response to both gases at 200oC. The film showed higher sensitivity to NO2 than to NH3, presumably due to the adsorption mechanism between sensing an oxidizing gas and reducing gas.
