Microstructural characterization of electron beam evaporated tungsten oxide films for gas sensing applications
Ahsan, M., Tesfamichael, T., Bell, J., & Blackford, M. G. (2009) Microstructural characterization of electron beam evaporated tungsten oxide films for gas sensing applications. In Proceedings of the 16th AINSE Conference on Nuclear and Complementary Techniques of Analysis, Lucas Heights, Sydney .
Tungsten trioxide is one of the potential semiconducting materials used for sensing NH3, CO, CH4 and acetaldehyde gases. The current research aims at development, microstructural characterization and gas sensing properties of thin films of Tungsten trioxide (WO3). In this paper, we intend to present the microstructural characterization of these films as a function of post annealing heat treatment. Microstructural and elemental analysis of electron beam evaporated WO3 thin films and iron doped WO3 films (WO3:Fe) have been carried out using analytical techniques such as Transmission electron microscopy, Rutherford Backscattered Spectroscopy and XPS analysis. TEM analysis revealed that annealing at 300oC for 1 hour improves cyrstallinity of WO3 film. Both WO3 and WO3:Fe films had uniform thickness and the values corresponded to those measured during deposition. RBS results show a fairly high concentration of oxygen at the film surface as well as in the bulk for both films, which might be due to adsorption of oxygen from atmosphere or lattice oxygen vacancy inherent in WO3 structure. XPS results indicate that tungsten exists in 4d electronic state on the surface but at a depth of 10 nm, both 4d and 4f electronic states were observed. Atomic force microscopy reveals nanosize particles and porous structure of the film. This study shows e-beam evaporation technique produces nanoaparticles and porous WO3 films suitable for gas sensing applications and doping with iron decreases the porosity and particle size which can help improve the gas selectivity.
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|Item Type:||Conference Paper|
|Keywords:||Gas Sensors, Thin Film Coatings, Nanostructure Characterisation, Surface Characterisation, Nanomaterials|
|Subjects:||Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > CONDENSED MATTER PHYSICS (020400) > Surfaces and Structural Properties of Condensed Matter (020406)
Australian and New Zealand Standard Research Classification > TECHNOLOGY (100000) > NANOTECHNOLOGY (100700) > Nanomaterials (100708)
Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > CONDENSED MATTER PHYSICS (020400) > Condensed Matter Physics not elsewhere classified (020499)
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering
Past > Schools > School of Engineering Systems
|Copyright Owner:||Copyright 2009 Please consult the authors.|
|Deposited On:||17 Feb 2010 01:46|
|Last Modified:||29 Feb 2012 14:06|
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