Browsing by Author "Chiou, Ai-Huei"

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Induced NH2 bonding of carbon nanotubes using NH3 plasma-enhanced chemical vapor deposition
(2012-04-01)
Chiou, Ai-Huei
;
Chang, Yu-Ming
;
Wu, Wen-Fa
;
Chou, Chang-Ping
;
Hsu, Chun-Yao
Plasma-enhanced chemical vapor deposition was used to modify the multiwall carbon nanotubes (MWCNTs) using ammonia (NH3) plasma. For various durations of NH3 plasma treatment, a scanning electron microscope, X-ray, Raman spectroscopy and contact angle measurement were used to ascertain several characteristics of the MWCNTs. The experimental results show that: (1) the length of the MWCNTs is reduced, if the duration of the plasma treatment is increased; (2) the NH3 plasma treatment can incorporate amine (NH2-) or amino (NH-) functional groups onto the MWCNT surface; (3) the plasma treated carbon nanotubes become more hydrophilic.
Optimization of the Sputtering Process Parameters of AZO Films with Multiple Quality Characteristics
(2012-01-01)
Wen, Dong-Cherng
;
Hsu, Chun-Yao
;
Chiou, Ai-Huei
;
機械工程學系
;
Department of Mechanical Engineering
Aluminum-doped zinc oxide (AZO) films were deposited on polyethylene terephthalate (PET) by radio frequency magnetron sputtering. The influence of the various deposition parameters (R.F. power, substrate-to-target distance, substrate temperature, deposition time) on electrical, morphological and optical properties of AZO/PET films was investigated. The use of grey-based Taguchi method to determine the optimization of the process parameters by considering multiple performance characteristics has been reported. The electrical resistivity and the average transmittance of the AZO films were improved by increasing the substrate temperature. Finds based on the grey relational analysis show that the lowest electrical resistivity of AZO films to be about 1.6 x 10(-3) Omega-cm, and visible range transmittance about 80%.
The effect of differently sized Ag catalysts on the fabrication of a silicon nanowire array using Ag-assisted electroless etching
(2013-06-01)
Chiou, Ai-Huei
;
Chien, Tse-Chang
;
Su, Ching-Kuei
;
Lin, Jheng-Fong
;
Hsu, Chun-Yao
A simple and low cost method to generate single-crystalline, well-aligned silicon nanowires (SiNWs) of large area, using Ag-assisted electroless etching, is presented and the effect of differently sized Ag catalysts on the fabrication of SiNWs arrays is investigated. The experimental results show that the size of the Ag catalysts can be controlled by adjusting the pre-deposition time in the AgNO3/HF solution. The optimum pre-deposition time for the fabrication of a SiNWs array is 3 min (about 162.04 +/- 38.53 nm Ag catalyst size). Ag catalysts with smaller sizes were formed in a shorter pre-deposition time (0.5 min), which induced the formation of silicon holes. In contrast, a large amount of Ag dendrites were formed on the silicon substrate, after a longer pre-deposition time (4 min). The existence of these Ag dendrites is disadvantageous to the fabrication of SiNWs. Therefore, a proper pre-deposition time for the Ag catalyst is beneficial to the formation of SiNWs. SiNWs were synthesized in the H2O2/HF solution system for different periods of time, using Ag-assisted electroless etching (pre-deposition of the Ag catalyst for 3 min). The length of the SiNWs increases linearly with immersion time. From TEM, SAED and HRTEM analysis, the axial orientation of the SiNWs is identified to be along the [001] direction, which is the same as that of the initial Si wafer. The use of HF may induce Si-H-x bonds onto the SiNWarray surface. Overall, the Ag-assisted electroless etching technique has advantages, such as low temperature, operation without the need for high energy and the lack of a need for catalysts or dopants. (C) 2012 Elsevier B.V. All rights reserved.
The use of the grey-Taguchi method for the optimization of a silicon nanowires array synthesized using electroless Ag-assisted etching
(2013-09-01)
Chiou, Ai-Huei
;
Wu, Wen-Fa
;
Chen, Ding-Yeng
;
Hsu, Chun-Yao
;
機械工程學系
A simple and convenient method for the production of silicon nanowires (SiNWs) that are single crystalline, well aligned and which have large area is direct synthesis onto p-type (100) silicon (Si) wafers, using electroless Ag-assisted etching, in which Ag is both the oxidant and the catalyst. This study proposes a method for the optimization of the etching process parameters for SiNW arrays with multiple performance characteristics, using grey-Taguchi analysis. The effect of the etching process parameters (etching time, solution (AgNO3/HF) temperature, silver nitrate (AgNO3) concentration and hydrogen fluoride (HF) concentration) on the length, diameter, structure, and morphology of the SiNW arrays were studied. In the confirmation runs, grey relational analysis shows that the length of the SiNW arrays is increased from 15.80 to 23.07 mu m, and the diameter is decreased from 76.77 to 66.65 nm. Further, the linear relationship for the SiNW arrays can be adjusted by increasing the etching time (from 15 to 45 min) and the solution temperature (from 25 to 75 degrees C). The axial orientation of the SiNWs is determined to be along the [001] direction, which is the same as that of the initial Si wafer. The large area SiNW arrays have potential applications in interconnect, bio-technology and optoelectronic devices.