Controlled synthesis of gas sensing Cr2−xTixO3 films by electrostatic spray assisted vapour deposition and their structural characterisation

Titanium substituted chromium oxide Cr2−xTixO3 is an excellent gas sensor material, which can be applied at the elevated temperatures for the detection of combustible and toxic gases. A versatile and cost-effective Electrostatic Spray Assisted Vapour Deposition (ESAVD) is used to prepare Cr2−xTixO3 materials. The crystalline phase, composition and microstructure of Cr2−xTixO3 films prepared by ESAVD are characterised by X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy and Raman microscope. In this paper, we report the relationships between the processing parameters and the microstructure of the deposited films. The Cr1.8Ti0.2O3 films with more ordered porous structure and smaller grain size deposited by ESAVD show a typical sensing behaviour with the sensitivity of around 45% at 500 °C to 500 ppm ammonia.