Title :
Tailoring of the Gas Sensing Performance of TiO2 Nanotubes by 1-D Vertical Electron Transport Technique
Author :
Hazra, A. ; Bhattacharyya, P.
Author_Institution :
Dept. of Electron. & Telecommun. Eng., Indian Inst. of Eng. Sci. & Technol. at Shibpur, Howrah, India
Abstract :
Aligned TiO2 nanotubes (NTs), having diameter of 75 ± 10 nm and length of 280 ± 20 nm were synthesized by electrochemical anodization technique. Two types of device configurations, viz., planar/lateral and metal-insulator-metal (MIM)/vertical sensor structures were fabricated with TiO2 NTs as the sensing layer. Vertical 1-D electron transport technique of MIM configurations was found to be very effective over the random (across the connected tubes) electron transport kinetics of planar devices, in determining the vapor (ethanol) sensor characteristics like response time and operating temperature. The optimum operating temperature of ethanol sensing was found to be much lower (75 °C) in case of MIM compared with its planar counterpart (150 °C). In addition, MIM configuration offered four and six times faster response and recovery times, respectively, compared with the planar ones toward 100-ppm ethanol at 75 °C. Sensing performance of the device configuration was correlated with the corresponding grain boundary model and carrier transport time with the help of 1-D electron transport path constituted of TiO2 NT array.
Keywords :
MIM devices; anodisation; electrochemical analysis; electrochemical sensors; electron transport theory; gas sensors; nanosensors; nanotube devices; organic compounds; titanium compounds; MIM configuration; TiO2; Vertical 1-D electron transport technique; carrier transport; electrochemical anodization technique; ethanol sensor; gas sensor; grain boundary model; metal-insulator-metal-vertical sensor structure; nanotube; planar-lateral sensor structure; temperature 150 degC; temperature 75 degC; vapor sensor characteristics; Arrays; Electrodes; Ethanol; MIM devices; Temperature sensors; Time factors; Ethanol sensor; TiO₂ nanotubes (NTs); TiO2 nanotubes (NTs); fast response; low temperature; metal–insulator–metal (MIM) configuration; metal??insulator??metal (MIM) configuration; planar configuration; vertical electron transport;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2014.2342277