Browsing by Author "Lin, Chen-Han"

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Effect of anions on the oxidation and reduction of hydrogen peroxide on the gold nanoparticle-deposited carbon fiber paper electrode
(2015-10-20)
Lin, Chen-Han
;
Wei, Lan-Yi
;
Lee, Jhao-Hong
;
Lien, Chun-Lung
;
Lu, Chung-Hsiang
The nanostructured gold has been shown to catalyze the oxidation of hydrogen peroxide (H2O2), an important analyte for clinical diagnosis. However, little is known about the effect of anions on its catalytic activity. In this study the gold nanoparticles (AuNP) of average size of 30-80 nm were electrodeposited on the carbon fiber paper (CFP) electrode to explore the effect of anions, such as phosphate, sulfate, nitrate, acetate, chloride and hydroxide ions, on the AuNP-catalyzed H2O2-oxidation. In phosphate solution the AuNP-deposited CFP (AuNP/CFP) exhibited high catalytic activity to H2O2. However, the catalytic activity of AuNP was severed blocked in solutions containing chloride, sulfate, nitrate, and acetate ions. Although hydroxide was shown to facilitate the catalysis of AuNP, the oxidation of H2O2 was greatly interfered by the gold oxide formation in 0.05 M NaOH. A strong dipole moment between adsorbed anions, such sulfate, nitrate and acetate, and AuNP is suggested to block the access of H2O2 molecules to the surface of AuNPs. This postulation is demonstrated by the finding that the electrochemical active surface area of AuNP/CFP is 0.90 +/- 0.02 cm(2), 0.79 +/- 0.08 cm(2), 0.66 +/- 0.09 cm(2), 0.45 +/- 0.04 cm(2), 0.42 +/- 0.08 cm(2) and 0.15 +/- 0.08 cm(2), in 0.05 M hydroxide, phosphate, bicarbonate, nitrate, acetate and sulfate solutions, respectively. These results indicate that the microenvironment near the surface of nanostructured Au is important to determine the catalytic activity of Au to H2O2. (C) 2015 Elsevier Ltd. All rights reserved.
Effects of HfO(2) buffer layer thickness on the properties of Pt/SrBi(2)Ta(2)O(9)//HfO(2)/Si structure
(2008-07-01)
Leu, Ching-Chich
;
Lin, Chen-Han
;
Chien, Chao-Hsin
;
Yang, Ming-Jui
;
電子工程學系及電子研究所
We investigated structural and characteristic changes in thin HfO(2) films (< 10 nm) by varying their thicknesses and also examined their influence on the properties of Pt/SrBi(2)Ta(2)O(9)/HfO(2)/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures. HfO(2) films with different thicknesses were found to exhibit rather distinct characteristics and to profoundly affect the properties of the fabricated MFIS capacitor. We found that, when employing 3.2-nm-thick HfO(2) as the buffer layer, the MFIS capacitor showed good memory performance at low operation voltage. However, this study demonstrated that some of the HfO(2) limited its application in MFIS memory, even though it is the most promising alternative gate dielectric material.
Effects of HfO2 buffer layer thickness on the properties of Pt/SrBi2Ta2O9//HfO2/Si structure
(2008-07-01)
Leu, Ching-Chich
;
Lin, Chen-Han
;
Chien, Chao-Hsin
;
Yang, Ming-Jui
;
電子工程學系及電子研究所
We investigated structural and characteristic changes in thin HfO2 films (< 10 nm) by varying their thicknesses and also examined their influence on the properties of Pt/SrBi2Ta2O9/HfO2/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures. HfO2 films with different thicknesses were found to exhibit rather distinct characteristics and to profoundly affect the properties of the fabricated MFIS capacitor. We found that, when employing 3.2-nm-thick HfO2 as the buffer layer, the MFIS capacitor showed good memory performance at low operation voltage. However, this study demonstrated that some of the HfO2 limited its application in MFIS memory, even though it is the most promising alternative gate dielectric material.
Properties of Pt/SrBi2Ta2O9/BL/Si MFIS structures containing HfO2, SiO2, and Si3N4 buffer layers
(2007)
Leu, Ching-Chich
;
Leu, Chia-Feng
;
Chien, Chao-Hsin
;
Yang, Ming-Jui
;
Huang, Rui-Hao
The physical and electrical properties of Pt/SrBi2Ta2O9 (SBT)/buffer layer (BL)/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures incorporating HfO2, SiO2, and Si2N4 as buffer layers were investigated. When employing HfO2 as the buffer layer, an MFIS structure exhibiting a high memory ratio was constructed, presumably because of the SBT characteristics and the high quality of the HfO2 layer on the Si substrate. This study demonstrates that HfO2 is one of the best buffer-layer materials for ferroelectric memory applications. (c) 2007 The Electrochemical Society.