Title: Hybrid gas sensor having TiO₂ nanotube arrays and SnO₂ nanoparticles

Authors: I. Kim; W-Y. Choi

Addresses: Department of Chemical Engineering, Ajou University, Suwon 443-749, South Korea; R&D Division, Maccon Inc., Bucheon 421-170, South Korea ' Department of Metal and Materials Engineering, Gangneung-Wonju National University, Ganneung 210-702, South Korea; Research Institute for Dental Engineering, Gangneung-Wonju National University, Gangneung 210-702, South Korea

Abstract: To obtain a good performance of gas detection, a newly-designed metal oxide semiconductor gas sensor has been fabricated by micromachining process. The micro platform consisted of Pt heater and electrode and its size was 2.5 mm × 2.5 mm. For hybrid sensing materials, such as SnO₂ nanoparticles and TiO₂ nanotube arrays were deposited on the micro platform. To obtain a clean and open window of TiO₂ nanotube, two-step anodic oxidation was conducted. The diameter of window and length of TiO₂ nanotubes were ∼60 nm and ∼5.5 µm, respectively. Detection performances for CO and CH₄ gases were investigated with operation circuit at operating temperature of 100°C and 300°C, respectively. The power consumption of fabricated micro platform was 28 mW and 94 mW at 2 V and 4 V of heater voltages, respectively. High sensitivity and short response time were observed. The microstructures of gas sensor were systemically characterised by FESEM and X-ray diffraction patterns.

Keywords: MOS gas sensors; metal oxide semiconductors; micromachining; MEMS; microelectromechanical systems; TiO2 nanotubes; titanium dioxide; titania; SnO2 nanoparticles; tin dioxide; CO; carbon monoxide detection; CH4; methane detection; hybrid sensing materials; nanotechnology; microstructure.

DOI: 10.1504/IJNT.2017.082459

International Journal of Nanotechnology, 2017 Vol.14 No.1/2/3/4/5/6, pp.155 - 165

Published online: 24 Feb 2017 *

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