Study On The Preparation And Properties Of Al-Doped ZnO Sensing Thin Films

The ZAO thin film has attracted much attention as its excellent optical ,electrical and gas sensitive properties. The ZAO thin film has many advantages , such as abundance natural resources, easy production procedure, low cost, no toxicity, high thermal stability and chemical stability. The ZAO thin film will become the new delegate of the Transparent Conduction Oxide Films.There are still many problems of the preparation of ZAO, such as the reproducibility and the reliability of the technological parameters are bad. Through studing the preparation and the technology parameter, we analyzes the relationship between the structure, optical and electrical properties and the technology parameters. In this thesis, the ZAO thin film is prepared in the JGP450 sputtering apparatus by the method of co-reactive magnetron sputtering technology. Through changing the distance of the target, the reaction gas pressure, the RF sputtering power of Zn, the DC sputtering power of Al.The influence of processing parameters on the properties of the ZAO thin film was discussed in detail from a lot of experiment date. The optimum parameters are generalized. That is, the oxygen flue is 1.0sccm, the argon flue is 21sccm, the RF sputtering power of Zn is 115W, the DC sputtering power of Al is 30W,the deposition time is 30min,the target-substrate distance is 6cm,the ZAO thin film is annealed in nitrogen about one and a half hours, the annealing temperature is 4500C. Using the optimum parameters to make ZAO thin film, the resistivity is 4.9×10^-3Ω·cm, the transmissivity in visible region is about 83%.The structure, optical and electrical properties of the ZAO thin film were analyzed by XRD, SEM, ultraviolet and infrared photometer, keithley-2700,van de Pauw method. We study that when Al sputtering power is 15 W, 25W, 30W, 40W respectively, the gas sensing and response - recovery time of the ZAO film on the alcohol gas, NO₂ gas, LPG gas. And we discuss the gas sensing mechanism of ZAO film on alcohol gas as well as NO₂ gas.The gas sensitive test of ZAO film shows that the sensitivty of ZAO film which Al sputtering power is 30W is higher. In the end, this thesis comes up wth problems discovered in the test and look forward to the prospect of thin film sensor.