Study On Preparation And Gas-sensing Propertiy Of Zn Ti And Zn Sn Co-sputtering Thin Films

The ZnO thin film is a important semiconducting material, it has the outstanding photoelectricity performance and the gas sensitive properties. In addition, it has many advantages, such as raw material in the nature reserves rich, low cost, the high thermal stability and the chemical stability. It has the broad application prospect. After doping with it, the thin film performance may obtain enhances largely, So develops this aspect the research has vital practical significance.Along with the advance in technology, automated, integrated, the miniaturized degree enhancement as well as the people environmental protection consciousness enhancement, How to control harmful gas become the universal social question. This request gas monitor can realize automatic, prompt, fast and stable. But the first question needs to solve is using which material in manufacturing the gas sensor. At present the thin film gas material still at the research and development stage, still has many problems. For example: The operating temperature high, the service life short, the doping unstable, the gas mechanism does not have the system theory explanation and so on. To solve this kinds of problem, study on the preparation and the performance research of the gas-sensing thin film is the essential way.This article uses the double target co-sputtering method, prepared different adulterant and the different doping quantity thin films, and study the influence of them to the ZnO thin film gas performance. Our goal is to seek the best preparation craft and discussion mechanism and the selectivity of gas-sensing thin film. In Zn and Ti co-sputtering experiment, through adjustment distance of target, working gas current capacity, sputtering power and so on, We prepared different quantity of Ti in the Ti-doped ZnO thin film, after the XRD test analysis and the gas performance research to the thin film, We summarized the best preparation parameter: The target distance 6.5㎝, Ar and the O2 relative flow is 23:8, working intensity of pressure 1.0Pa, Zn the direct-current sputtering power 115W, Ti radio frequency sputtering power is 200W, the deposition time 20 minutes. The preparation thin film crystallization quality is good, and also has high sensitivity to the LPG gas. We found out the best operating temperature is 380℃. In Zn and Sn double target co-sputtering experiment, we although has not get Sn-doped ZnO thin film, but after we study the microstructure and the gas sensitivity of the thin films, we determined that the thin film we prepared includes SnO2 and the ZnSnO3 two ingredients. Particularly when Sn sputtering power is 70W, we made the sole component ZnSnO3 thin film, this sample had the remarkable sensitivity and the selectivity to the ethanol gas. The maximal sensitivity to the 200ppm ethanol gas achieved 30, and it also can examine the low concentration ethanol gas as 10ppm. To the ethanol gas its best operating temperature is 320℃. Finally we using the surface chemistry and the adsorption chemistry theory discussed the gas sensitivity mechanism of doped ZnO thin film.