Study On Preparation And Optical Gas Sensing Characteristics Of Ti-doping Tungsten Oxide Films By Co-sputtering

Nano tungsten oxide films material is an important functional material. It isinvestigated and exploited broadly because of its gaschromic property, electrochromicproperty, photochromic property, etc.Especially gaschromic property is applied to gassensors extensively.The Tungsten oxide thin films were deposited on glass substrates by DC-reactivemagnetron sputtering technology.The Ti-doping Tungsten oxide films were deposited byco-sputtering. and then Heat treated at350℃,450℃a nd550℃.Optical properties、micro-structural properties of Tungsten oxide films, Ti:WO₃thin films were studied.The films were characterized with step devices、ultraviolet visible transmittanceSpectrophotometer （UV-Vis） and X-ray diffraction （XRD）. As results of study, withthe spattering power of titanium increased，films deposition velocity becomes rapidness.The film with oxygen partial pressure is30%、the spattering power of titanium is40wand annealed with450℃crystallizes well. The Tungsten oxide thin film with oxygenpartial pressure is30%and annealed with450℃crystallizes well among the comparedof different oxygen partial pressure. As the Heat treated temperature increased, theTungsten oxide thin amorphous films began to crystallize. And finally, the Tungstenoxide thin films with monoclinic structure were obtained, which grew merit on thedirection of （200）. The Tungsten oxide thin film with oxygen partial pressure is30%and annealed with450℃crystallizes better than that annealed with550℃.The optical gas sensing properties of WO₃thin films and Ti-doped WO₃thin filmswere studied. The optical gas sensing properties of the films in various depositedconditions were tested and analysised to C₂H₅OH gas of600ppm、H2of600ppm andNO2of600ppm. The optical gas sensitivity mechanism of WO₃and Ti-doped WO₃films are discussed in this thesis. As results of study, the WO₃thin film with oxygenpartial pressure is30%and without heat treatment was performance excellent of opticalgas sensing characteristics in C₂H₅OH gas at300℃, which was senseing well in H2gasat350℃. The Ti-doped WO₃film with oxygen partial pressure is30%、the spattering power of titanium is40w and without heat treatment was performance excellent ofoptical gas sensing characteristics in NO₃gas at300℃. The Ti-doped WO₃film withoxygen partial pressure is30%、the spattering power of titanium is10w and withoutheat treatment has goog selectivity to H2gas at300℃. The Ti-doped WO₃film withoxygen partial pressure is30%、the spattering power of titanium is40w and withoutheat treatment has goog selectivity to NO₃gas at300℃.The sensitve part of the filmswas in the range of380nm to550nm region. So, the study has definite reference valuefor new generation of " gas-optical " sensor.