| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 96 === There is a growing demand for developing a sensing system to measure hydrogen not only for industry applications but also for human safety especially in the purpose of hydrogen energy automobile. The sensing materials are including conducting polymers and metal oxide. In this thesis metal oxide ZnO is chosen as sensing material. A good sensor should be characterized by high sensitivity, wide dynamic range, fast response, good reproducibility, small size, and low cost. Surface acoustic wave (SAW) sensing devices are promising candidates to pursue the goals.
In this thesis, a 145 MHz oscillator based on 128P° PYX-LiNbOB3 BSAW resonator was fabricated. Dual delay line configuration is employed to eliminate temperature and humidity fluctuations. Because of nanostructure materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, to function as a hydrogen sensor, the Pt coated ZnO nanorods were coated on the delay line of the resonator as sensing film. The SAW sensor is then used to measure various hydrogen concentrations at ppm level. The results showed that the proposed SAW sensor system exhibits fast response, good sensitivity and short-term repeatability at room temperature. The experimental results are batter than the results based on HCl doped polyaniline nanofibers.
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