| Summary: | 碩士 === 國立中興大學 === 奈米科學研究所 === 103 === In this research, we used spin coating method to make ZnO seed layer, and then growing massive high quality nanowires via aqueous solution method. After growth, we combined grew nanowires and self-make arrayed electrodes by dielectrophoresis method, and successfully produced room temperature CO sensing device.
With the characterization of field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), grazing incidence X-ray diffraction (GIXRD), field emission transmission electron microscope (FE-TEM), and photoluminescence (PL), we knew that the grew nanowires were single crystalline and belongs to the wurtzite structure. As the growth time increasing from half hour to six hours, the average length would increase from 0.69 ± 0.03 μm to 2.40 ± 0.06 μm, and the average diameter would increase from 21.36 ± 0.48 nm to 96.17 ± 4.31 nm. After growing for two hours, the nanowire prefer to grow along [002], and the crystalline is best for growing for six hours. All the nanowires possess energy gap-emission at the wave length of about 378 ~ 383 nm.
On the other hand, we fabricated a chip that contains 60 pairs of electrodes which the gap are about 2.28 μm, and put nanowires cross onto the electrodes to make sensing devices. From the I-V curve, we can know that the device are Schottky contact. And finally, we test the devices under room temperature and the alternating ambient between 10% CO and air. The best driving voltage were found as 2 V among 1 V to 3 V, and the average response and recovery time were about 48.37 and 65.61 seconds, and the response magnitude is about 6.8% at room temperature.
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