Growth of zinc-oxide nanorods and its applications for gas sensor

• Main Authors: Yueh-tien Tsou, 鄒岳庭
• Other Authors: Bohr-ran Huang
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/42667567235383786894

碩士 === 國立雲林科技大學 === 電子與資訊工程研究所 === 93 === ZnO crystal is an important semiconductor material and has been investigated widely for its piezoelectric, electrical, optoelectronic and optic properties. In this thesis, the main interest is in the development of ZnO NRs (nanorods) and its sensing properties of oxygen. In our experiment, ZnO NRs of 150~250 nm in radius and 4~5 μm in height had been synthesized in the thermal CVD system. Morphology, Crystal quality and defect level were examined by SEM (Scanning-Electron-Microscopy), XRD (X-Ray Diffraction) patterns and PL (Photo-luminescence) measurement. According to the recent research, various gases such as O2, N2O and ethanol… etc. can react with ZnO to form bonds of physisorption or chemisorption. A series of experiments were designed to measure gas sensitivity under different temperatures and partial oxygen pressures of the ZnO NRs based gas sensors. This study showed that the sensitivity is proportional to the oxygen partial pressure and defect. Higher operating temperature can improve the sensitivity significantly. It is found that highest oxygen partial pressure of 500Torr or sample grew with highest defect concentration has the best sensitivity but has the longest recovery delay. Operating temperature of 350℃ has the better sensitivity compared with lower operating temperature. It is also found that the recovery delay was mainly due to the sensitivity, that is higher sensitivity has the longer recovery delay. Finally, a light source of UV lamp was found to reduce the recovery delay.