Measurement and Application of Lithium Niobate Bulk Wave Sensors with Graphene Film

• Main Authors: Shu-Yu Chuang, 莊舒伃
• Other Authors: Yung-Yu Chen
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/88609872229863369832

碩士 === 大同大學 === 機械工程學系(所) === 102 === Global warming have been an important issue for many years. It’s because the carbon dioxide and other greenhouse gases are increasing constantly. With industrial development and progress, the emission of exhaust from factory、automobile and motorcycle is the culprit caused by rising carbon dioxide concentration in atmospheric. A variety of policies to reduce carbon dioxide emissions has been undertaken internationally, in order to monitor the emissions of carbon dioxide effectively and trace concentrations of atmospheric carbon dioxide, it's necessary to develop a low cost and high sensitivity sensor for carbon dioxide. The surface acoustic wave gas sensor has many characteristics like good stability, sensitivity, and low cost is adequate for use as carbon dioxide sensing. However, the LFE form gas sensor through bulk wave to detect, only used in liquid sensing in the past. This study try to combine the characteristic of graphene high sensitive for environment changes to improve the defect which LFE sensor doesn’t apply to use in gas measure. Then make a lightweight and sensitive gas sensing devices. In this paper, we used 128°YXLiNbO3 as a substrate and graphene as a sensing layer, oscillated by the form of the Lateral Field Excited to develop a bulk wave sensors to measure carbon dioxide. We use finite element analysis (COMSOL) to analyze the property of LFE seneor, frequency response and conductivity changes, and compared with experimental results. The results showed that when pass into 1000ppm carbon dioxide to chamber, the frequency drift about 210Hz, consistent with its trends and forecasts.