8-12 July 2013
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=13&confId=32"><font color=#ff0000>SAIP2013 PROCEEDINGS AVAILABLE</font></a>

Synthesis, characterization and gas sensing applications of Tungsten Trioxide

10 Jul 2013, 09:40
20m
Oral Presentation Track A - Division for Condensed Matter Physics and Materials DCMPM2

Speaker

Mr Malcolm Govender (CSIR)

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Main supervisor (name and email)<br>and his / her institution

Bonex W. Mwakikunga, BMwakikunga@csir.co.za
CSIR-NCNSM

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

No

Abstract content <br> &nbsp; (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.

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

PhD

Primary author

Co-authors

Dr Augusto Machatine (University of Pretoria) Dr Bonex Mwakikunga (CSIR-NCNSM) Prof. Herbert Kunert (University of Pretoria)

Presentation Materials

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