Due to the increased awareness of living and industrial safety, carbon monoxide detectors must be geared towards better portability and sensitivity. Metal oxide semiconductor sensors should possess advantages such as heat and corrosion resistance,
low cost materials, and ease of miniaturization. This thesis applied ball milled and powdered ZnO and SnO2 to manufacture into paste, then used the screen printing method deposited ZnO and SnO2 paste film and silver electrode on glass substrate. The influence
on sensing film materials, temperature, time of heat treatment, and temperature of measurement was investigated. The samples were fabricated and measured by setting up self-measurement apparatus. The data was analyzed the changes of resistance under different air and carbon monoxide environments. This is followed by analysis of both
surface topography and microstructure of the sensing film under OM and SEM.
Experiment reveals that samples under different annealing process yield different surface morphology and micro structure while at the beginning of the heat treatment, epoxy evaporates from the sample brought about porous structure. Annealing at higher temperature sample will have more rough surface and better sensitivity in detecting carbon monoxide. After epoxy removed, heat treatment mechanism is then switched to sinter ZnO and SnO2 powders. the longer the samples are sintered, the lower the sensitive.
Sensing films composited with ZnO and SnO2 will have better carbon monoxide sensitivity at 300oC but its sensitivity decays at a faster rate than samples working at 250 oC despite the slightly weaker sensitivity. Sensing films with pure ZnO will have higher sensitivity compared to pure SnO2 one. With the increase of SnO2 proportion, carbon monoxide sensitivities of detectors decreases, however, its life time can be improve significantly.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-1128112-160922 |
| Date | 28 November 2012 |
| Creators | Fu, chung-ho |
| Contributors | Tsung-ming Tsai, Ting-chang Chang, Tai-fa Young, Mei-ling Wu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1128112-160922 |
| Rights | user_define, Copyright information available at source archive |
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