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The Assessment for Sensitivity of a NO2 Gas Sensor with ZnGa2O4/ZnO Core-Shell Nanowires—a Novel Approach
Micro Systems Technology Center, ITRI South, Industrial Technology Research Institute, Tainan 709, Taiwan
College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
Chemical Engineering Department, National Chung-Cheng University, Chia-Yi, 621, Taiwan
Department of Electronic Engineering National University of Tainan, Tainan, 700, Taiwan
National Nano Device Laboratories, Tainan 741, Taiwan
* Authors to whom correspondence should be addressed.
Received: 15 March 2010; in revised form: 23 March 2010 / Accepted: 24 March 2010 / Published: 30 March 2010
Abstract: The application of novel core-shell nanowires composed of ZnGa2O4/ZnO to improve the sensitivity of NO2 gas sensors is demonstrated in this study. The growth of ZnGa2O4/ZnO core-shell nanowires is performed by reactive evaporation on patterned ZnO:Ga/SiO2/Si templates at 600 °C. This is to form the homogeneous structure of the sensors investigated in this report to assess their sensitivity in terms of NO2 detection. These novel NO2 gas sensors were evaluated at working temperatures of 25 °C and at 250 °C, respectively. The result reveals the ZnGa2O4/ZnO core-shell nanowires present a good linear relationship (R2 > 0.99) between sensitivity and NO2 concentration at both working temperatures. These core-shell nanowire sensors also possess the highest response (<90 s) and recovery (<120 s) values with greater repeatability seen for NO2 sensors at room temperature, unlike traditional sensors that only work effectively at much higher temperatures. The data in this study indicates the newly-developed ZnGa2O4/ZnO core-shell nanowire based sensors are highly promising for industrial applications.
Keywords: ZnGa2O4; ZnO; core shell; nanowire; NO2; gas sensor; sensitivity
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MDPI and ACS Style
Chen, I.-C.; Lin, S.-S.; Lin, T.-J.; Hsu, C.-L.; Hsueh, T.J.; Shieh, T.-Y. The Assessment for Sensitivity of a NO2 Gas Sensor with ZnGa2O4/ZnO Core-Shell Nanowires—a Novel Approach. Sensors 2010, 10, 3057-3072.
Chen I-C, Lin S-S, Lin T-J, Hsu C-L, Hsueh TJ, Shieh T-Y. The Assessment for Sensitivity of a NO2 Gas Sensor with ZnGa2O4/ZnO Core-Shell Nanowires—a Novel Approach. Sensors. 2010; 10(4):3057-3072.
Chen, I-Cherng; Lin, Shiu-Shiung; Lin, Tsao-Jen; Hsu, Cheng-Liang; Hsueh, Ting Jen; Shieh, Tien-Yu. 2010. "The Assessment for Sensitivity of a NO2 Gas Sensor with ZnGa2O4/ZnO Core-Shell Nanowires—a Novel Approach." Sensors 10, no. 4: 3057-3072.