Preparation Of Flammable Gas Sensor And Property Investigation

The present status of selectivity research and new development of semiconductor gas sensor isintroduced and the doping technology of metal oxide semiconductor gas sensors is commented. The dopingof the semiconductor gas sensors and its influence on se nsitivity and selectivity of the gas sensors ispresented. based thin film is one of the most widely researched material, optimizing the sensitivity toadapt to actual application by doped with other element is a developing trend.In this article, TiO₂ doping thin films and Pt doping thin films gas sensor were prepared by themethod of DC magnetron sputtering. The effects of different technological parameters, such as sputteringvoltage, sputtering current, annealing temperature and so on, upon the thin film structure and gas sensitivecharacters were investigated in this paper. We used the technology of XRD to detect the structures andproperties of the films, and discussed how to influence on the sensitivity, and analyzed the sensitivity theoryof the thin films. The experiments show that the doped with Pt thin films have high sensitivity towardacetone, and the sensing property is better at higher operating temperature. the doped with TiO₂ thinfilms showed wonderful sensing properties toward ammonia vapor, and the sensitivity has relation withanneal temperature, the sample annealed by 700 has excellent sensitivity and selectivity, and responsetime.The thesis also introduced some ordinary structure of gas element, and discussed advantage anddisadvantage side of them. the failure and failure causation of the gas sensor were analyzed, the failure ofsensors was included the excursion of primal resistance and primal sensitivity. Several factors such as thestructure of sensor material, operating temperature and working environment can cause the failure of gassensor.