A room temperature surface acoustic wave CO sensor based on Au-coated ZnO nanorods
Date Issued
2009
Date
2009
Author(s)
Fan, Ching-Hsiang
Abstract
There is a growing demand for developing a sensing system to measure carbon monoxide (CO) not only for industry applications but also for human health in the recent years. CO is generated from the combustion of the organic matter with insufficient oxygen supply, which is colorless, odorless and tasteless. Moreover, CO is able to poison the noble metals making poor performance on the catalyst like Pt used in fuel cells. Due to the fatal danger and poisoning effect, the demand for CO detection at room temperature with high sensitivity, stability, selectivity and short response time is urgently required.he previous research of the CO sensor employed the variety of sensing material as the metal oxide semiconductor with various nanostructure, and most of them showed the operating temperature higher than 80?C causing large power consumption and problems of size reduction of the heater circuit. Since the surface acoustic wave (SAW) sensor device having high sensitivity to the surface perturbation, a CO SAW sensor based on Au-coated ZnO nanorods is realized to pursue the goals of CO detection at the room temperature. In the thesis, a SAW resonator is fabricated on 128?YX-LiNbO3 with the central frequency of 145 MHz. The ZnO nanorods and the adsorption of gold nanoparticles are adopted as the sensing material with periodic pattern structure coated on the delay line of the surface. A dual delay line configuration was also applied to eliminate the environmental fluctuations. Due to the ZnO nanorods posing high surface-to-volume ratio, fast charge diffusion rate and the room temperature catalyzing properties of the gold nanoparticles, we have successfully demonstrated the CO SAW sensor having fast response, high sensitivity, and short-term repeatability at room temperature, which is a good candidate for the portable CO monitoring application.
Subjects
SAW
Oscillator
CO sensor
128-YX-LiNbO3
Gold nanoparticles
ZnO nanorods
Catalyst
Periodic structure
SDGs
Type
thesis
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