Controlled synthesis of gas sensing Cr_(2-x)Ti_xO_3 films by electrostatic spray assisted vapour deposition and their structural characterisation

摘要

Titanium substituted chromium oxide Cr_(2-x)Ti_xO_3 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 Cr_(2-x)Ti_xO_3 materials. The crystalline phase, composition and microstructure of Cr_(2-x)Ti_xO_3 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 Cr_(1.8)Ti_(0.2)O_3 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℃ to 500 ppm ammonia.