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Semiconductor TiO2-Al2O3 thin film gas sensors derived from aqueous particulate sol-gel process
, Article Materials Science in Semiconductor Processing ; Vol. 27, issue , 2014 , p. 711-718 ; Sharif University of Technology
Abstract
Nanostructured TiO2-Al2O3 films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and aluminum chloride were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the porosity. The effect of Al:Ti molar ratio was studied on the crystallization behavior of the products. X-ray diffraction (XRD) revealed that the powders crystallized at 800°C, containing anatase-TiO2, rutile-TiO2 and cubic-Al2O3 phases. Furthermore, it was found that Al2O3 retarded the anatase to rutile transformation. Transmission electron microscope (TEM) image showed that one of the smallest crystallite sizes was...
Comparison of single and binary oxide sol-gel gas sensors based on titania
, Article Solid State Sciences ; Volume 10, Issue 7 , 2008 , Pages 884-893 ; 12932558 (ISSN) ; Fray, D. J ; Ghorbani, M ; Sharif University of Technology
Elsevier Masson SAS
2008
Abstract
A systematic comparison of single and binary metal oxides TiO2, TiO2-Ga2O3 and TiO2-Er2O3 thin film gas sensors with nanocrystalline and mesoporous microstructure, prepared by a new particulate sol-gel route, was conducted. The gas sensitivity was increased by introduction of Ga2O3 and Er2O3 into TiO2 film via two mechanisms, firstly through the inhibition of anatase-to-rutile transformation, since the anatase phase accommodates larger amounts of adsorbed oxygen, and secondly through the retardation of grain growth, since the higher surface area provides more active sites for gas molecule adsorption. The binary metal oxide gas sensors exhibited a remarkable response towards low...
Development of nanocrystalline TiO2-Er2O3 and TiO2-Ta2O5 thin film gas sensors: Controlling the physical and sensing properties
, Article Sensors and Actuators, B: Chemical ; Volume 141, Issue 1 , 2009 , Pages 76-84 ; 09254005 (ISSN) ; Fray, D. J ; Sharif University of Technology
2009
Abstract
A systematic comparison of single and binary metal oxide TiO2, TiO2-Er2O3 and TiO2-Ta2O5 thin film gas sensors with nanocrystalline and mesoporous microstructure, prepared by sol-gel route, was conducted. The gas sensitivity was increased by secondary phase introduction into TiO2 film via two mechanisms, firstly due to the inhibition of anatase-to-rutile transformation, since the anatase phase accommodates larger amounts of adsorbed oxygen, and secondly due to the retardation of grain growth, since the higher surface area provides more active sites for gas molecule adsorption. The binary metal oxide gas sensors exhibited a remarkable response towards low concentrations of CO and NO2 gases at...