Flexible ZnO thin film acoustic wave device for gas flow rate measurement. (2nd July 2020)

• Record Type: Journal Article
• Authors: Zhang, Qian; Wang, Yong; Tao, Ran; Torun, Hamdi; Xie, Jin; Li, Yifan; Fu, Chen; Luo, Jingting; Wu, Qiang; Ng, Wai Pang; Binns, Richard; Fu, Yong Qing
• Is Part Of: Journal of micromechanics and microengineering. Volume 30:Number 9(2020:Sep.)
• Publication Date: 2020-07-02
• Subjects: surface acoustic wave -- flexible device -- gas flow rate measurements; Microelectromechanical systems -- Periodicals; Micromechanics -- Periodicals; 621.38105
• DOI: 10.1088/1361-6439/ab9d2a
• Languages: English
• ISSNs: 0960-1317

Abstract

Abstract: In this work, ZnO/Al thin film based flexible acoustic wave devices are demonstrated for their applications in gas flow rate measurements based on the changes in temperature of the devices. A good sensitivity of gas flow rate can be achieved, mainly because thin film based device has a large temperature coefficient of frequency of ∼280 ppm K −1, owing to the large coefficient of thermal expansion of aluminum foil. A heat source is used to enhance the sensitivity of the thin film device by introducing a temperature offset. The flexible acoustic wave device shows a high sensitivity, fast response times, and a good repeatability for measurement of the flow rate of nitrogen. When the flexible acoustic wave device is bent and attached onto the inner wall of a pipe, the device exhibits good performance for monitoring the gas flow rate, demonstrating its applications of flow rate measurement on curved or randomly shaped surfaces.