Browsing by Author "Lin, Hsiao-Wei"

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Facile Fabrication of TiO(2) Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method
(2012-01-01)
Lin, Hsiao-Wei
;
Chang, Yung-Huang
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Self-organized anodic titanium dioxide nanorod arrays were fabricated using a two-stage anodization method from superimposed Ti-Al layers deposited on quartz substrates. The morphology of nanorods could be controlled by the anodizing conditions of the aluminum (first stage) and the titanium layer (second stage). The first stage of anodization process controls the diameter and density of nanorods and the second stage of anodization controls the height of nanorods. Therefore, we could fabricate nanorod arrays with desired aspect ratio and density under specific anodizing conditions. Furthermore, we used TiO(2) nanorod arrays as the field ionization anode of a gas sensor, and the morphology of nanorods has shown to have a high correlation with the working voltage of gas sensing. The TiO(2) nanorods possess good selectivity and low working voltage under different atmosphere and their working electric field is lower than gas sensing using carbon nanotubes and ZnO nanowires as the anode. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.013201jes].
Facile Fabrication of TiO2 Nanorod Arrays for Gas Sensing using Double-Layered Anodic Oxidation Method
(2012-01-01)
Lin, Hsiao-Wei
;
Chang, Yung-Huang
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Self-organized anodic titanium dioxide nanorod arrays were fabricated using a two-stage anodization method from superimposed Ti-Al layers deposited on quartz substrates. The morphology of nanorods could be controlled by the anodizing conditions of the aluminum (first stage) and the titanium layer (second stage). The first stage of anodization process controls the diameter and density of nanorods and the second stage of anodization controls the height of nanorods. Therefore, we could fabricate nanorod arrays with desired aspect ratio and density under specific anodizing conditions. Furthermore, we used TiO2 nanorod arrays as the field ionization anode of a gas sensor, and the morphology of nanorods has shown to have a high correlation with the working voltage of gas sensing. The TiO2 nanorods possess good selectivity and low working voltage under different atmosphere and their working electric field is lower than gas sensing using carbon nanotubes and ZnO nanowires as the anode. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.013201jes].
Growth Mechanism of Self-Assembled TiO2 Nanorod Arrays on Si Substrates Fabricated by Ti Anodization
(2012)
Chang, Yung-Huang
;
Lin, Hsiao-Wei
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The growth rate and the growth mechanism are investigated by examining the results of scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) on TiO2 nanorods fabricated in the second anodization process through the nanopores of anodic aluminum oxide. Due to the strong electric field of 1.86 GV/m to 1.33 GV/m, the average ultra-fast growth rate of 250 nm/s is observed, and the abrupt increase of height reaches to 85.2% of its destined height in the early growth stage of 0.6 s. Then the growth rate decreases when the electric field decays with the increase of height, and it is interrupted by the dielectric breakdown under an electric field of 0.65 GV/m. According to the XPS analyzes, the TiO2 species on the outer shell of nanorods are observed, and the sub-oxides, Ti2O3 and TiO, are exhibited after Ar+ ions sputtering. It is proposed that the bottom growth mechanism is identified by the analyzes upon SEM and XPS results. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.034209jes] All rights reserved.
Ultrafast Initial Growth Rate of Self-Assembled TiO(2) Nanorod Arrays Fabricated by Ti Anodization
(2011-01-01)
Chang, Yung-Huang
;
Lin, Hsiao-Wei
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The growth mechanism of TiO(2) nanorods fabricated by the anodization of Ti films using a mask of anodic aluminum oxide is investigated by examining the growth rate and morphology of the fabricated nanorods. It is found that the growth rate is 250 nm/s within the first 0.1 s at 117 V and decreases abruptly to 0.79 nm/s after 3 s. In addition, the diameter of the nanorods is larger near the top than near the root of the nanorods. A growth mechanism is proposed to explain these interesting phenomena. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3496404] All rights reserved.
Ultrafast Initial Growth Rate of Self-Assembled TiO2 Nanorod Arrays Fabricated by Ti Anodization
(2011-01-01)
Chang, Yung-Huang
;
Lin, Hsiao-Wei
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The growth mechanism of TiO2 nanorods fabricated by the anodization of Ti films using a mask of anodic aluminum oxide is investigated by examining the growth rate and morphology of the fabricated nanorods. It is found that the growth rate is 250 nm/s within the first 0.1 s at 117 V and decreases abruptly to 0.79 nm/s after 3 s. In addition, the diameter of the nanorods is larger near the top than near the root of the nanorods. A growth mechanism is proposed to explain these interesting phenomena. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3496404] All rights reserved.