Sensing Performance of Precisely Ordered TiO2 Nanowire Gas Sensors Fabricated by Electron-Beam Lithography
<p>Device fabrication process: (<b>a</b>) Thermal oxidation of bulk Si wafer; (<b>b</b>) Deposition of Cr/Au for contact electrodes; (<b>c</b>) Deposition of Cr/Au on the backside of the Si subtract for the microheater; (<b>d</b>) E-beam lithography and TiO<sub>2</sub> deposition followed by the lift-off process and (<b>e</b>) illustration of electrode and sensing film design on Si chips and (<b>f</b>) photo images of the TiO<sub>2</sub> nanowire array bridging at the integrated electrodes.</p> ">
<p>(<b>a</b>) Schematic of testing configuration; (<b>b</b>) thermal image of the sensor with an applied voltage of 9 V; (<b>c</b>) temperature responses of TiO<sub>2</sub> nanowire gas sensor as a function of applied voltage to the backside of the microheater (inset of packaged sensor).</p> ">
<p>(<b>a</b>) SEM image of TiO<sub>2</sub> nanowire gas sensor (<b>b</b>) XRD patterns of TiO<sub>2</sub> thin film with 450 °C annealing for 1 h and without the annealing process.</p> ">
<p>Band model showing the formation of a space charge region in a p-type TiO<sub>2</sub> in presence of surface acceptor states before (<b>a</b>) and after (<b>b</b>) adsorption of ambient oxygen (E<sub>vac</sub>: potential of the electron in vacuum; x<sub>0</sub>: depletion width).</p> ">
<p>(<b>a</b>) Transient responses at various operation temperatures (with the injection absolute mass quantity of 7.5 μg); (<b>b</b>) normalized sensing responses at various operation temperatures of (a); and (<b>c</b>) reaction times of the TiO<sub>2</sub> nanowire sensors tested at injection mass of 7.5 to 15.0 μg.</p> ">
<p>(<b>a</b>) Transient sensing responses and (<b>b</b>) reaction times of the TiO<sub>2</sub> nanowire sensors at 300 °C with various ethanol injection mass quantities.</p> ">
<p>(<b>a</b>) Transient sensing responses and (<b>b</b>) reaction times of the TiO<sub>2</sub> nanowire sensors at 300 °C with various ethanol injection mass quantities.</p> ">
<p>(<b>a</b>) Transient sensing responses and (<b>b</b>) reaction times of the TiO<sub>2</sub> nanowire sensors at 300 °C with various ethanol injection mass quantities.</p> ">
<p>(<b>a</b>) Transient sensing responses and (<b>b</b>) reaction times of the TiO<sub>2</sub> nanowire sensors at 300 °C with various ethanol injection mass quantities.</p> ">
<p>(<b>a</b>) Reliability test for devices (<b>b</b>) Effect of ethanol concentrations on the sensing response and corresponding standard deviations of TiO<sub>2</sub> nanowire sensors under various operating temperatures.</p> ">
Abstract
:1. Introduction
2. Experimental Section
3. Results and Discussion
4. Conclusions
Acknowledgments
References
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Tian, W.-C.; Ho, Y.-H.; Chen, C.-H.; Kuo, C.-Y. Sensing Performance of Precisely Ordered TiO2 Nanowire Gas Sensors Fabricated by Electron-Beam Lithography. Sensors 2013, 13, 865-874. https://doi.org/10.3390/s130100865
Tian W-C, Ho Y-H, Chen C-H, Kuo C-Y. Sensing Performance of Precisely Ordered TiO2 Nanowire Gas Sensors Fabricated by Electron-Beam Lithography. Sensors. 2013; 13(1):865-874. https://doi.org/10.3390/s130100865
Chicago/Turabian StyleTian, Wei-Cheng, Yu-Hsuan Ho, Chao-Hao Chen, and Chun-Yen Kuo. 2013. "Sensing Performance of Precisely Ordered TiO2 Nanowire Gas Sensors Fabricated by Electron-Beam Lithography" Sensors 13, no. 1: 865-874. https://doi.org/10.3390/s130100865