Investigation And Preparation Of The Thin Film-Type Gas Sensor

Nowadays,as a new type of sensor, gas sensor developed very quickly. The thin film materials have a particular microstructure, wonderful physical and chemical properties, excellent surface character, which make the thin films technology become the key of the gas sensor technique. Now thin films doping is becoming a focus of study.In this article, ZnO thin films and doping ZnO thin films gas sensor were prepared by the method of DC magnetron sputtering, the ZnO thin films gas sensor with lower working temperature(about 220°C), have high sensitivity and excellent selectivity towards acetone that can resist the interfere of other organic gas. Then the influence of annealing upon the structure of thin films was detected through XRD, and the mechanism of ZnO thin film sensor property towards acetone was discussed through comparing the components of the tested gas with unreacted gas by the I-R measure technique.The ZnO doped with TiO2 showed wonderful sensing properties towards ethanol vapor, and the sensitivity has relation with doping time, the XRD was carried out to analyze the change of the structure of thin films before doping and after doping, we found that doping can restrain the growth of grain. The ZnO thin film doped with La2O3 was broad-spectrum gas sensor towards a lot of organic gas. At the same time, we prepared SnO2 thin films doped with ZnO, this sensor showed high sensitivity both towards ethanol and acetone vapor.In this article, the failure and failure causation of the gas sensor were analyzed, the failure of sensors was included the excursion of primal resistance and primal sensitivity. Several factors such as the structure of sensor material, operating temperature and working environment can cause the failure of gas sensor.