Browsing by Author "Chen, S. Y."

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A Theoretical Investigation of Surface-enhanced Sum-frequency Generation
(2016-01-01)
Yeh, Y. L.
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Lei, J.
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Chen, S. Y.
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Chang, A. H. H.
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Lin, C. K.
Following the surface enhanced Raman scattering (SERS), we shall investigate the possibility of observing surface-enhanced sum-frequency generation (SESFG), which refers to the transformation of ordinary vibrational SFG (i.e. singly resonant) into SESFG. Two mechanisms of SESFG will be studied; one is due to the transformation of singly-resonant vibrational SFG into doubly resonant vibrational SFG (that is, both vibrationally resonant and Raman-scattering resonant) and the other is due to the enhancement of the polarizability in addition to the original vibrational resonance in vibrational SFG.
A Theoretical Investigation of Surface-enhanced Sum-frequency Generation
(2016-01)
Yeh, Y. L.
;
Lei, J.
;
Chen, S. Y.
;
Chang, A. H. H.
;
Lin, C. K.
Following the surface enhanced Raman scattering (SERS), we shall investigate the possibility of observing surface-enhanced sum-frequency generation (SESFG), which refers to the transformation of ordinary vibrational SFG (i.e. singly resonant) into SESFG. Two mechanisms of SESFG will be studied; one is due to the transformation of singly-resonant vibrational SFG into doubly resonant vibrational SFG (that is, both vibrationally resonant and Raman-scattering resonant) and the other is due to the enhancement of the polarizability in addition to the original vibrational resonance in vibrational SFG.
Effects of nitrogen-doping on the microstructure, bonding and electrochemical activity of carbon nanotubes
(2009-02-01)
Lin, Y. G.
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Hsu, Y. K.
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Wu, C. T.
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Chen, S. Y.
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Chen, K. H.
Vertically aligned carbon nanotubes produced with in-situ doping of nitrogen (CN(x) NTs) during chemical vapor deposition exhibit unique structural and electrochemical properties, which are strongly correlated with their nitrogen (N) doping level. In this work, the effects of N-doping on CN(x) NTs have been systematically investigated via microstructure and bonding studies, electron-transfer (ET) behaviors, and subsequent electrochemical deposition of catalyst. The CN(x) NTs doped with an optimal N level, while showing a nearly reversible ET behavior, in fact exhibit uniform and high density of surface defects. These surface defects are desirable for further modification and/or nucleation of catalytic particles on the surface of CN(x) NTs to form a composite electrode for electrochemical energy device applications such as fuel cells and capacitors. (c) 2008 Elsevier B.V. All rights reserved.
Electrically responsive ZnO nanotubes for controlled release of biomolecules
(2017-01-01)
Lin, C. C.
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Chen, Y. W.
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Hsiao, C. S.
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Chen, S. Y.
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材料科學與工程學系
We developed a novel electro-responsive drug delivery device by depositing fluorescein isothiocyanate (FITC)-loaded zinc oxide nanotubes (ZTs) onto indium tin oxide (ITO)/polyethylene terephthalate (PET) substrates (called FITC-ZTs-ITO/PET). With a large payload of FITC up to 0.98 mmol g(-1), the FITC-ZTs simultaneously provide a burst-like FITC release and a repeated step-like release after application of an electrical field at specific resonant frequencies. Additionally, FITC-ZTs-ITO/PET is biocompatible with both HeLa and MRC5 cells for ZT concentrations below 50 mu g/ml. These results demonstrate that FITC-ZTs-ITO/PET is a new platform that can provide local, on-demand electrically responsive drug release for biomedical applications.
Electrically responsive ZnO nanotubes for controlled release of biomolecules (vol 43, pg S802, 2017)
(2017-12-01)
Lin, C. C.
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Chen, Y. W.
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Hsiao, C. S.
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Chen, S. Y.
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材料科學與工程學系
Endurance study of switching characteristics in NiO films
(2007-03-01)
Lee, M. D.
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Lo, C. K.
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Peng, T. Y.
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Chen, S. Y.
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Yao, Y. D.
Bi-stable switching effect has been studied in nickel oxide. lms with three different thicknesses. The best sample of our experiments was 150-nm NiO film. Its resistance ratio between high and low states was 3.6 in endurance measurement. The maximum resistance ratio in I-V curve could reach two orders of magnitude, and it could endure over 200 times of reverse processes with the ratio remaining about 1.46. This indicates that the nickel oxide has potential to be a promising material on resistance random access memory. (C) 2006 Elsevier B.V. All rights reserved.
Enhancement of light output intensity by integrating ZnO nanorod arrays on GaN-based LLO vertical LEDs
(2008)
Chiu, C. H.
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Lee, C. E.
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Chao, C. L.
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Cheng, B. S.
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Huang, H. W.
Enhancement of light output intensity for GaN-based vertical light-emitting diodes (LEDs), combining wafer bonding and the laser lift-off (LLO) process, employing an omnidirectional extraction surface with synthesized single-crystal ZnO nanorod arrays in aqueous solution at room temperature is presented. The light output intensity and wall-plug efficiency of the GaN-based LLO vertical LED with the omnidirectional extraction surface by ZnO nanorod arrays shows 38.9 and 41.2% increases, respectively, at 200 mA current injections compared to that of a vertical LED without ZnO nanorod arrays. The ZnO nanorod arrays not only support a current spreading layer but enhance the probability of photon escape through the omnidirectional extraction surface. (C) 2008 The Electrochemical Society.
Epitaxial layer of MgO (001) grown on Si(001)wafer by e-beam evaporation
(2006-09-01)
Lee, M. D.
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Lo, C. K.
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Peng, T. Y.
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Yau, K. L.
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Chen, S. Y.
MgO(0 0 1) has been growing successfully on Fe/Pd/Cu/Si(1 0 0) by e-beam evaporation as examined by X-ray diffraction and high resolution transmission microscope. We present the magnetic peculiarity of crystal structure Fe(0 0 1)/Pd(0 0 1)/Cu(0 0 1) on Si(0 0 1) substrate. The magnetic properties of the sample were measured by magneto-optical Kerr effect which shows an in-plane magnetocrystalline anisotropy. (C) 2006 Elsevier B. V. All rights reserved.
Fouling analysis of polysulfone ultrafiltration membranes used for drinking water treatment
(2011)
Zhao, B. Q.
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Huang, C. P.
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Chen, S. Y.
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Wang, D. S.
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Li, T.
Natural organic matter (NOM) plays a significant role in the fouling of ultrafiltration membranes in drinking water treatment processes. For a better understanding of the interaction between fractional components of NOM and polysulfone (PS) ultrafiltration membranes used for drinking water treatment, fouling and especially the physically irreversible fouling of natural organic matter were investigated. Resin fractionation, fluorescence excitation-emission matrix (EEM) spectroscopy, fourier transform infrared spectroscopy (FTIR), contact angle and a scanning electron microscope (SEM) were employed to identify the potential foulants. The results showed that humic acid and fulvic acid of small size were likely to permeate the membrane, while the hydrophobic fraction of humic and fulvic acid and aromatic proteins tended to be rejected and retained. Organic compounds such as proteins, humic substances, and polysaccharide-like materials, were all detected in the fouling layer. The physically irreversible fouling of the PS membrane seemed to be mainly attributed to the hydrophobic fraction of humic substances.
Growth of Multiple Metal/Semiconductor Nanoheterostructures through Point and Line Contact Reactions
(2010-10-01)
Wu, W. W.
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Lu, K. C.
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Wang, C. W.
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Hsieh, H. Y.
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Chen, S. Y.
Forming functional circuit components in future nanotechnology requires systematic studies of solid-state chemical reactions in the nanoscale Here, we report efficient and unique methods, point and line contact reactions on Si nanowtres, fabricating high quality and quantity of multiple nanoheterostructures of NiSi/Si and investigation of NiSi formation in nanoscale By using the point contact reaction between several Ni nanodots and a Si nanowire carried out in situ in an ultrahigh vacuum transmission electron microscopy, multiple sections of single-crystal NISI and Si with very sharp interfaces were produced in a Si nanowire Owing to the supply limited point contact reaction, we propose that the nucleation and growth of the sugar cane-type NISI grains start at the middle of the point contacts between two Ni nanodots and a Si nanowire The reaction happens by the dissolution of Ni into the Si nanowire at the point contacts and by interstitial diffusion of Ni acorns within a Si nanowire. The growth of NISI stops as the amount of Ni in the Ni nanodots is consumed Additionally, without lithography, utilizing the line contact reaction between PS nanosphere-mediated Ni nanopatterns and a nanowire of Si. we have fabricated periodic multi-NiSi/Si/NiSi heterostructure nanonowires that may enhance the development of circuit elements in nanoscale electronic devices Unlike the point contact reaction, suicide growth starts at the contact area in the line contact reaction, the different silicide formation modes resulting from point and line contact reactions are compared and analyzed A mechanism on the basis of flux divergence is proposed for controlling the growth of the nanomultiheterostructures
Growth of Multiple Metal/Semiconductor Nanoheterostructures through Point and Line Contact Reactions
(2010-10-01)
Wu, W. W.
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Lu, K. C.
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Wang, C. W.
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Hsieh, H. Y.
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Chen, S. Y.
Forming functional circuit components in future nanotechnology requires systematic studies of solid-state chemical reactions in the nanoscale Here, we report efficient and unique methods, point and line contact reactions on Si nanowtres, fabricating high quality and quantity of multiple nanoheterostructures of NiSi/Si and investigation of NiSi formation in nanoscale By using the point contact reaction between several Ni nanodots and a Si nanowire carried out in situ in an ultrahigh vacuum transmission electron microscopy, multiple sections of single-crystal NISI and Si with very sharp interfaces were produced in a Si nanowire Owing to the supply limited point contact reaction, we propose that the nucleation and growth of the sugar cane-type NISI grains start at the middle of the point contacts between two Ni nanodots and a Si nanowire The reaction happens by the dissolution of Ni into the Si nanowire at the point contacts and by interstitial diffusion of Ni acorns within a Si nanowire. The growth of NISI stops as the amount of Ni in the Ni nanodots is consumed Additionally, without lithography, utilizing the line contact reaction between PS nanosphere-mediated Ni nanopatterns and a nanowire of Si. we have fabricated periodic multi-NiSi/Si/NiSi heterostructure nanonowires that may enhance the development of circuit elements in nanoscale electronic devices Unlike the point contact reaction, suicide growth starts at the contact area in the line contact reaction, the different silicide formation modes resulting from point and line contact reactions are compared and analyzed A mechanism on the basis of flux divergence is proposed for controlling the growth of the nanomultiheterostructures
Incorporation Behaviors of In and Ga in the Two-Heater MOVPE Growth of InGaN Films
(2016)
Fu, S. F.
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Cheng, C. H.
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Lee, F. W.
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Chen, S. Y.
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Liao, B. W.
Incorporation behaviors of In and Ga of InGaN films grown by the two-heater metal-organic vapor-phase epitaxial horizontal reactor is investigated by varying growth parameters, such as the substrate temperature, ceiling temperature and reactor pressure. Two In loss mechanisms are observed by the analysis of the concentration and temperature profiles in the deposition zone. The gas-phase parasitic-loss mechanism (activation energy similar to 34.2 +/- 0.1 kcal/mol) is significant in the ceiling temperature T-ceil >= 800 degrees C and at substrate temperature (T-sub) of 600 degrees C. The decomposition-loss mechanism, which arises from In desorption on the growing surface, is significant in T-sub > 625 degrees C region. The desorption activation energy obtained is 28.0 +/- 0.1 kcal/mol, which is close to that of InN (25-26 kcal/mol). This suggests the In decomposition-loss mechanism in InGaN growth does not differ substantially from that in binary InN growth. On the other hand, the gas-phase parasitic-loss mechanism of Ga is negligible in the growth condition that we have explored. Exception is found for reactor pressure at T-ceil = 950 degrees C, where both factors advantageous and disadvantageous to Ga incorporation are unambiguously observed. We have proposed explanation for the above observation. (C) The Author(s) 2016. Published by ECS. All rights reserved.
Influence of pulsed laser annealing on the optical properties of ZnO nanorods
(2012-08-01)
Lin, T. N.
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Huang, C. P.
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Shu, G. W.
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Shen, J. L.
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Hsiao, C. S.
"The effect of pulsed laser annealing (PLA) on the photoluminescence (PL) properties of ZnO nanorods was investigated. As the fluence of pulsed laser increases, the UV PL in ZnO nanorods shows a general increasing trend, except at a range of fluences from 10 to 70?mJ/cm2. It is found that the treatment with the PLA at the fluence of 70?mJ/cm2 leads to a larger improvement of crystalline properties than that with rapid thermal annealing (RTA). The relationship between PL intensity and fluence of pulsed lasers can be well explained by a combination of the deterioration in surface crystallinity and the increased donor densities after PLA."
Multiple heterostructures of Ni2Si/Si formed by the point contact reaction
(2009)
Hao Ouyang
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Cheng, Ming-Ting
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Shiu, Yung-Ruei
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Lo, Shen-Chuan
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Wu, Wen-Wei
The high quality multiple heterostructures of Ni2Si/Si in a nanowire of Si can be formed by using the point contact reaction between several Ni nanodots and a Si nanowire carried out in-situ in an ultrahigh vacuum transmission electron microscopy. The fabricated multi-nano-heterostructures may enhance the development of circuit elements in nano-scale electronic devices. The unusual tetragonal Ni2Si (I4/mcm) phase rather than the commonly observed HCP Ni2Si (P63/m) was identified in the multiple heterostructures of Ni2Si/Si with the existence of surface oxide. The corresponding electronic structure and kinetic paths of phase transformations will be simulated and discussed.
Synergistic targeting to HER2-positive breast cancer via nanocapsules with tunable ligand density and magnetic targeting
(2014-07-01)
Chiang, C.
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Chen, S. Y.
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材料科學與工程學系
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Department of Materials Science and Engineering
Synthesis of ethanol-soluble few-layer graphene nanosheets for flexible and transparent conducting composite films
(2011-07-22)
Nguyen, D. D.
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Tai, N. H.
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Chueh, Y. L.
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Chen, S. Y.
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Chen, Y. J.
We report a facile method of preparing few-layer graphene nanosheets (FLGs), which can be soluble in ethanol. Atomic force microscopy and high-resolution transmission electron microscopy studies reveal that FLGs have average thicknesses in the range of 2.6-2.8 nm, corresponding to 8-9 layers. A graphene/nafion composite film has a sheet resistance of 9.70 k Omega/sq at the transmittance of 74.5% (at 550 nm) while the nafion film on polyethylene terephthalate has a sheet resistance of 128 k Omega/sq at transmittance of 90.0%. For the cycling/bending test, almost no change in resistance was exhibited when the film was bent at an angle up to 140 degrees, and no obvious deviation in resistance could be found after 100 bending cycles was applied. In addition, an FLGs-poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) composite layer was demonstrated as the effective hole transporting layer to improve the hole transporting ability in an organic photovoltaic device, with which the power conversion efficiency was enhanced from 3.10% to 3.70%. The results demonstrated the promising applications of FLGs on graphene-based electronics, such as transparent electrode and flexible conducting film.
Tertiary nitrogen nitrogen removal using simultaneous partial nitrification, anammox and denitrification (SNAD) process in packed bed reactor
(2017-05-01)
Chen, W. H.
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Chiang, Y. A.
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Huang, Y. T.
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Chen, S. Y.
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Sung, S.
The study aimed to polish wastewater effluent from an activated treatment system for nitrogen removal by a packed bed bioreactor (PBR). The nitrogen removal via simultaneous partial nitrification, anammox and denitrification (SNAD) process was investigated with different hydraulic retention times (HRTs). The results show that both effluent ammonia-and nitrate-nitrogen concentrations approached to 0 mg/L at the HRT as low as 3 h. The total nitrogen removal efficiency decreased from an average of 84% at both 18- and 24-h HRTs to 38% at 3-h HRT. This low nitrogen removal efficiency was due to the presence of incomplete degradation of organic nitrogen at shorter HRTs. The analysis using quantitative real-time polymerase chain reaction resolves that the ratio of ammonia-oxidizing bacteria (AOB) to the domain Eubacteria changed limited in the range between 2.8 and 4.0% during the continuous operation. Meanwhile, the nitrite-oxidizing bacteria (NOB) increased from 0.0 to 2.9% when the HRT was gradually reduced to 3 h. The anammox bacteria accounting for 30.5% of microbial consortia dominated the AOB and the NOB at the 3-h HRT. In sum, inorganic form of nitrogen in a typical wastewater plant effluent could be efficiently polished via SNAD process in the PBR. (C) 2017 Elsevier Ltd. All rights reserved.