A novel ethanol gas sensor based on ZnO-microwire
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A novel ethanol gas sensor based on ZnO-microwire Fei Li • Heqiu Zhang • Lizhong Hu • Yingmin Luo • Yu Zhao • Yu Qiu • Jiuyu Ji Lunlun Yue
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Received: 28 July 2013 / Accepted: 30 August 2013 / Published online: 11 September 2013 Ó Springer Science+Business Media New York 2013
Abstract One-dimensional (1D) ZnO microwires were successfully synthesized by chemical vapor deposition and their structural and morphological properties were analyzed by X-ray diffraction and scanning electron microscopy, demonstrating that the microwires were single crystalline with perfect hexagonal structure and smooth surface. Using these 1D microstructures, we fabricated a novel ZnO-based ethanol gas sensor. Operating at room temperature, the sensor was found to have good sensing characteristics. The reliability and stability of the sensor could be improved by connecting multiple 1-wire devices (1-WD) in parallel into a multi-wires device. In interior natural lighting environment and under 3 V bias, the response and recovery time of the 1-WD to 200 ppm ethanol gas were \10 s and about 300 s, respectively, and the minimum and maximum detection limit were about 2 and 200 ppm, respectively. A sensing model was proposed for discussing the performance of the sensor. The simplicity in fabrication, low power consumption and low cost make the sensor suitable for practical application in many fields, especially in identifying driving under the influence and chemical industry monitoring.
1 Introduction In recent years, a variety of prototype sensors based on metal oxide semiconductors, such as ZnO, SnO2 and TiO2
F. Li H. Zhang L. Hu (&) Y. Luo Y. Zhao Y. Qiu J. Ji L. Yue School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, People’s Republic of China e-mail: [email protected]
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[1–3], have been developed. Especially, ZnO-based sensors have received the most attention due to ZnO’s colorful micro/nanostructures, such as nanoflakes, nanohelix, hollow microspheres, nanofibers, nanoparticles [4–9], and its fascinating physical and chemical properties, such as low toxicity, good thermal stability, good biocompatibility and high electron mobility. By using ZnO micro/nanostructures, all kinds of sensors, such as gas sensors, chemical sensors, biosensors, ultra violet (UV) sensors, have now been fabricated [1]. ZnO-based gas sensors can detect various toxic and inflammable gases, volatile organic compounds (such as CO, NO2, H2S, H2, ethanol) [6, 10–12] and humidity [13]. And for the sake of improving the sensitivity, repeatability and selectivity, researchers have made great efforts in the following aspects: the first is to dope or coat the sensing materials with common or rare/noble metal [9, 14–18], the second is to use nanostructures with high surface/volume ratio as sensing materials [12, 19–22], the third is to employ semiconductor hetero-junction [23] or surface acoustic wave device structure [13], and the forth is to make use of UV or visible light assisted technology [12, 25, 26]. A
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