Browsing by Author "Wang, Yen-Chi"

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Epitaxial single-crystal of GaSe epilayers grown on a c-sapphire substrate by molecular beam epitaxy
(2015-10-01)
Wu, Chia-Hsin
;
Yang, Chu-Shou
;
Wang, Yen-Chi
;
Huang, Hsi-Jung
;
Ho, Yen-Teng
In this study, hetero-epitaxy of GaSe epilayers on a c-sapphire substrate achieved using molecular beam epitaxy was demonstrated. The GaSe epitaxial growth was monitored using in situ reflection high-energy electron diffraction (RHEED). Streak RHEED patterns showed a flat and highly crystalline situation. Furthermore, two RHEED patterns were observed after 15min of growth, and they were correlated with the m-axis and a-axis of hexagonal GaSe. The single crystal of GaSe was verified using X-ray diffraction and high-resolution cross-section transmission electron microscopy. The full width at half-maximum of (0002) in the XRD rocking-curve spectrum of GaSe epilayer is obtain around 207arcsec, which is the smallest value observed to date. The epitaxial growth of GaSe demonstrated the feasibility of growing large-area epilayers.
Improving the detection of hydrogen peroxide of screen-printed carbon paste electrodes by modifying with nonionic surfactants
(2009-10-19)
Yuan, Chiun-Jye
;
Wang, Yen-Chi
;
Reiko, Ohara
;
生物科技學系
;
Department of Biological Science and Technology
Nonionic surfactants, such as Triton X-100 and Tween-20, were shown in this study to improve the electroatalytic activity of screen-printed carbon paste electrodes (SPCE) The electrochemical response of SPCE to hydrogen peroxide increased 8-10-fold with the modification of nonionic surfactants. In addition, the glucose biosensors fabricated from nonionic surfactant-modified SPCE exhibited 64-8 6-fold higher response to glucose than that fabricated from unmodified SPCE A concentration effect is proposed for nonionic surfactant to bring neutral reactants to the surface of electrode. Moreover, nonionic surfactant-modified SPCE exhibits a capability of repetitive usage and good reproducibility (R S D < 5%) in the measurement of H(2)O(2) Interestingly, the nonionic surfactant-modified SPCE exhibited an opposite effect to ascorbic acid, a common electroactive agent, which causes interference during clinical diagnosis The differential responses of nonionic surfactant-modified SPCE to H(2)O(2) and ascorbic acid Suggest its potential in the development of biosensors for clinical diagnosis (C) 2009 Elsevier B.V. All rights reserved