The Study of Gas Sensing in Polycrystalline WO3 Films Sensor and the Effect of Adding Iridium

• Main Authors: Chun-Cheng Hsieh, 謝淳政
• Other Authors: Shuchi Chao
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/07238062913338612011

碩士 === 國立交通大學 === 電子物理系所 === 95 === Recently, due to the wide-spreading consciousness of environmental protection and technological needs﹐more and more people begin to care for the problems of air and environmental pollution. Therefore, the study of gas sensor has been discussed gradually. However, there are some drawbacks of traditional gas sensors such as costs, heavy weight and time consuming and so many studies have been turned to focus on. semiconductor materials thin film gas sensor. Purpose of this research is to make a short､small､light and thin gas sensor to detect the H2S and general gas be used in our daily life. In the process of oxidization, the Poly-WO3 film is transparent and colorless. Moreover, it also changes its color during reduction and presents broad seeable spectrum which is able to absorb the frequency band. In this study, the tungsten oxide（WO3）thin films is prepared by reactive RF magnetron sputter. The film is then stabilized by annealing in 400℃ of 4 hours and doped small amount of iridium to improve the sensitivity. The sensors were operated at the different thickness and working temperature to analyze the effect and added catalyst to test their differences and changes. The result of experiment shows Polycrystalline WO3 Films is able to effect and change their electricity with H2S and gas. When working temperature increases or gas concentration changes, it makes the relative response. It is found the sensitivity of this sensor is better to detect gas. Also, when the working temperature is at 200℃ and the catalyst iridium is added, the sensor provides better sensitivity.