Browsing by Issue Date, starting with "2006-03-14"

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Luminescence of selective area growth of epitaxial ZnO nanowires and random-growth-oriented nanobelts
(2006-03-14)
Hsu, HC
;
Cheng, HM
;
Wu, CY
;
Huang, HS
;
Lee, YC
Epitaxial ZnO nanowires and random-growth-oriented nanobelts were grown on c-plane sapphire with and without a pre-coated ZnO epilayer film. On the pre-coated ZnO epilayer, ZnO nanowires are vertically aligned with good in-plane alignment as a result of homoepitaxy, whereas on the bare c-plane sapphire, besides a few nanowires vertically aligned with [0001]znO parallel to [0001](Al2O3), the nanowires were properly aligned with three-fold rotation symmetry. The ZnO nanowires are well-defined hexagonal crystals with diameters of 70-500 nm and lengths of up to several micrometres. In the junction regions between the pre-coated epilayer and the bare sapphire surface, however, ZnO nanobelts (nanoribbons) were found. Cathodoluminescence measurements revealed that the emission at 3.26 eV is correlated with free-exciton recombination and the broad green emission at 2.48 eV is attributed to surface defects. The stronger green emission implies that more surface defects exist on the side walls of nanowires and nanobelts. In Raman scattering, the E1 (LO) mode is sensitive to the orientation of nanostructure that is consistent with the cathodoluminescence results.
管管作品五首
(2006-03-15)
管管
Generation of frequency tunable polarization entangled photon pairs
(2006-03-15)
Yabushita, A
;
Kobayashi, T
;
電子物理學系
;
Department of Electrophysics
Photon pairs with correlated frequencies from an optical parametric system were generated by a continuous wave pump focused on a type-II nonlinear crystal with polarization entanglement. The polarization entanglement of the frequency resolved photons was measured under several typical configurations. By optimizing a condition, the degree of polarization entanglement was improved substantially. We proposed the application of the system, which can be used as a light source of wavelength division multiplexing quantum key distribution, optimizing the configuration of the photon-pair generation. (c) 2006 American Institute of Physics.
Two-stage genetic programming (2SGP) for the credit scoring model
(2006-03-15)
Huang, JJ
;
Tzeng, GH
;
Ong, CS
;
運輸與物流管理系註：原交通所+運管所
;
科技管理研究所
Credit scoring models have been widely studied in the areas of statistics, machine learning, and artificial intelligence (AI). Many novel approaches such as artificial neural networks (ANNs), rough sets, or decision trees have been proposed to increase the accuracy of credit scoring models. Since an improvement in accuracy of a fraction of a percent might translate into significant savings, a more sophisticated model should be proposed for significantly improving the accuracy of the credit scoring models. In this paper, two-stage genetic programming (2SGP) is proposed to deal with the credit scoring problem by incorporating the advantages of the IF-THEN rules and the discriminant function. On the basis of the numerical results, we can conclude that 2SGP can provide the better accuracy than other models. (c) 2005 Published by Elsevier Inc.
Anti-inflammatory effect of Lactobacillus casei on Shigella-infected human intestinal epithelial cells. (vol 176, pg 1228, 2006)
(2006-03-15)
Tien, M. -T.
;
Girardin, S. E.
;
Regnault, B.
;
Le Bourhis, L.
;
Dillies, M. -A.
管管作品五首
(2006-03-15)
管管
管管作品五首
(2006-03-15)
管管
管管作品五首
(2006-03-15)
管管
Optimization of the growth of the InGaP etch-stop layer by MOVPE for InGaP/GaAs HBT device application
(2006-03-15)
Hsieh, YC
;
Chang, EY
;
Yeh, SS
;
Chang, CW
;
Luo, GL
InGaP has high etching selectivity to GaAs. It can be used as the etch-stop layer to easily fabricate the InGaP/GaAs heterojunction bipolar transistors (HBTs). This process will also increase the uniformity and manufacturability of the HBT devices. However, the InGaP etch-stop layer will increase the energy barrier height that electrons have to overcome flowing from the collector to the subcollector, which will decrease the DC current gain of the device (T. Kobayashi, K. Taira, F. Nakamua, H. Kawai, J. Appl. Phys. 65 (1989) 4898). Therefore, the InGaP etch-stop layer has to be thin enough not to affect the device performance. But the spontaneous formation of the InxGa1-xAsyP1-y intermixing layer between GaAs/InGaP during the metal organic vapour-phase epitaxy (MOVPE) growth will affect the InGaP layer thickness needed as an effective etch-stop layer. In this paper, very thin InGaP layer was achieved with the suppression of InxGa1-xAsyP1-y formation by the optimization of the growth temperature and the gas switching sequence time. An effective 20 angstrom InGaP etch-stop layer was grown at 575 degrees C with interruption time of 3 s. Both STEM and PL data proved that the intermixing InxGa1-xAsyP1-y layer was eliminated and from the selective etching experiment, this 20 angstrom InGaP layer can stand 45 s etching by the H3PO4:H2O2:H2O = 1:1:20 solution. (c) 2005 Elsevier B.V. All rights reserved.
Optical characterization of ZnSe epilayers and ZnCdSe/ZnSe quantum wells grown on Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrates
(2006-03-15)
Ku, JT
;
Kuo, MC
;
Shen, JL
;
Chiu, KC
;
Yang, TH
Several approaches have been employed to grow high-quality ZnSe epilayers on Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrates. The ZnSe epilayers were characterized by photoluminescence spectroscopy. Migration enhanced epitaxy and inserting an in situ thermal annealing ZnSe buffer layer effectively reduced the intensity of deep level emissions from the ZnSe epilayer grown on a 6 degrees-tilted Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrate. Optimized conditions for growing high-quality ZnSe were used to deposit ZnCdSe/ZnSe multiple quantum wells on Ge/Ge0.95Si0.05/Ge0.9Si0.1/Si virtual substrates. Photoluminescence spectroscopy revealed quantum-confinement effect in the ZnCdSe multiple quantum wells. The evolution of the exciton emission peak energy and the linewidth as a function of temperature indicate a low density of localized sites in the sample with a well width of 1 nm. In the high-temperature regime, the thermal quenching of the excitonic emission intensity from ZnCdSe quantum well structures was governed by the thermal activation of carriers from quantum-well-confined states into barrier states. (c) 2006 American Institute of Physics.
Supermode-noise-free eighth-order femtosecond soliton from a backwar dark-optical-comb-injection mode-locked semiconductor optical amplifier fiber laser
(2006-03-15)
Lin, GR
;
Pan, CL
;
Chiu, IH
;
光電工程學系
;
Department of Photonics
A backward dark-optical-comb-injection mode-locked semiconductor optical amplifier fiber laser (SOAFL) with a femtosecond pulse width and an ultrahigh supermode-noise suppressing ratio (SMSR) is primarily demonstrated. The mode-locked SOAFL pulse with a spectral linewidth of 0.45 nm is shortened from 15 to 8.6 ps under chirp compensation in a 420 m long dispersion-compensated fiber, corresponding to a time-bandwidth product of 0.48. The eighth-order soliton is obtained by the nonlinearly soliton's compression of the chirp-compen sated SOAFL pulse in a 112 m long single-mode fiber at an input peak power of 51 W, providing the pulse width, the linewidth, and the nearly transform-limited time-bandwidth product are < 200 fs, 13.8 nm, and 0.34, respectively. The phase noise and integrated timing jitter at an offset frequency below 1 MHz are -105 dBc/Hz and 0.8 ps, respectively. An ultrahigh pulse-compression ratio of 43 and a SMSR of 87 dB for the eighth-order SOAFL soliton are reported. (c) 2006 Optical Society of America.
以離心方式製作奈米材料及所製得之奈米球及奈米線
(2006-03-16)
朝春光
;
郭金國
;
陳建中
;
陳蓉萱
本發明關於一種新穎的奈米材料製作方法，包括：(1)置一種或二種以上不同熔點之材料於具保溫效果的管材中並施以密閉封管；(2)抽真空使其處於真空之環境下，以阻止管材內之金屬於加熱時產生氧化；(3)將裝有該材料與奈米模板之真空封閉管材加熱至一種或二種以上材料熔點以上之溫度；(4)放入離心機系統，使其在不同的轉速操作或離心力之大小之條件下而形成奈米材料；依該方法所製得之奈米球、奈米線及奈米元件。
使用全像空間偏極模組之光學多埠循環器及其全像空間偏極模組
(2006-03-16)
蘇德欽
;
陳敬恒
本發明提供一種使用全像空間偏極模組之光學多埠循環器及其全像空間偏極模組，其係根據全像記錄材料特性和耦合波理論，提出一繞射式之全像空間偏離偏極器，用以取代傳統晶體式空間偏離偏極器，再提出全像空間偏極模組的設計，將之應用於3埠、4埠或多埠的光學循環器與光學隔離器的設計中。因此本發明具有偏極獨立、密集、高獨立、低偏極模色散和易於製作等優點，且埠的數目可容易的被增加。
具陣列式奈米孔洞之氧化鋁薄膜的製造方法
(2006-03-16)
朝春光
;
陳建仲
;
陳蓉萱
;
郭金國
本發明提出一種具陣列式奈米孔洞之氧化鋁薄膜的製造方法，首先提供一商用鋁基材，將商用鋁基材經過退火處理，再經過電解拋光處理，以使鋁基材表面呈現鏡面效果，並接著進行陽極處理，使鋁基材表面上形成一含有奈米級之數孔洞的氧化鋁薄膜，且孔洞呈現陣列式排列，再來進行熱處理，使鋁基材產生氧化反應，而使部分較小孔洞被產生氧化反應之氧化物因自我擴散效應填滿，使得孔洞均一化，最後再進行擴孔處理，以使孔洞擴張。本發明可簡化製程、便於控制製造過程之操作，並可在同時降低成本下，在氧化鋁薄膜上得出均一孔徑且具陣列式排列之奈米孔洞分佈。
High energy scattering amplitudes of superstring theory
(2006-03-20)
Chan, CT
;
Lee, JC
;
Yang, Y
;
電子物理學系
;
Department of Electrophysics
We use three different methods to calculate the proportionality constants among high-energy scattering amplitudes of different string states with polarizations on the scattering plane. These are the decoupling of high-energy zero-norm states (HZNS), the Virasoro constraints and the saddle-point calculation. These calculations are performed at arbitrary but fixed mass level for the NS sector of 10D open superstring. All three methods give the consistent results, which generalize the previous works on the high-energy 26D open bosonic string theory. In addition, we discover new leading order high-energy scattering amplitudes, which are still proportional to the previous ones, with polarizations orthogonal to the scattering plane. These scattering amplitudes are of subleading order in energy for the case of 26D open bosonic string theory. The existence of these new high-energy scattering amplitudes is due to the worldsheet fermion exchange in the correlation functions and is, presumably, related to the high-energy massive spacetime fermionic scattering amplitudes in the R-sector of the theory. (c) 2006 Elsevier B.V. All rights reserved.
Properties of photoluminescence in type-II ZnTe/ZnSe quantum dots
(2006-03-20)
Lin, TY
;
Lyu, DY
;
Chang, J
;
Shen, JL
;
Chou, WC
Temperature and time evolution of the photoluminescence (PL) intensity of bimodal ZnTe/ZnSe type-II quantum dots (QDs) were investigated. A particular temperature dependence of PL was observed in large QDs. PL decay of small QDs is composed of a faster initial component and a slower tail component whereas PL decay of large QDs simply comprises a fast component. All phenomena could be understood consistently by considering charge carrier transfer mechanism, band-bending effect, and the existence of nonradiative centers in the bimodal type-II QD array. We show that excitons play an important role in the emission properties of a self-assembled type-II QD system.
Facile synthesis toward the construction of an activity probe library for glycosidases
(2006-03-20)
Shie, TH
;
Chiang, YL
;
Lin, JJ
;
Li, YK
;
Lo, LC
Chemical probes that selectively label the glycoside hydrolase (GH) subfamilies have proven to be a powerful tool in GH-related research. We have previously demonstrated the design and synthesis of an activity probe for beta-glucosidase adopting a cassette-like design in a model study. Herein we report an improved synthetic route using (4-hydroxyphenyl)acetic acid 2-cyanoethyl ester as the precursor for the latent trapping device. Parallel syntheses were performed for the preparation of a library based oil the structure of a key intermediate. The recognition head of this library covers a series of six sugars, including alpha- and beta-D-Glc, alpha- and beta-D-Gal, alpha-D-Man and alpha-L-Fuc. Each member in this versatile intermediate library could serve as the building block in constructing an activity probe for GHs. As demonstrated in this study, three probes that have the 1,2-cis configuration were thus prepared for the first time to target alpha-D-glucosidase, alpha-D-galactosidase, and alpha-L-fucosidase, respectively. (c) 2006 Elsevier Ltd. All rights reserved.
Electrical properties of resistance switching V-doped SrZrO3 films on textured LaNiO3 bottom electrodes
(2006-03-21)
Liu, CY
;
Wang, A
;
Jang, WY
;
Tseng, TY
;
電子工程學系及電子研究所
Sputter-deposited V-doped SrZrO3 (SZO) films were deposited on textured LaNiO3 (LNO) bottom electrodes to investigate the resistance switching properties and reliabilities. The microstructures of the SZO and LNO films were characterized by x-ray diffraction. The resistance of the AI/V-doped SZO/LNO sandwich structures can be reversibly switched by operating with dc bias voltages or voltage pulses. The device with [100] orientated SZO film had better resistance switching properties and the resistance ratio was more than 1000. The effect of thermal treatment on resistance switching properties was investigated and different behaviour of the two leakage-states was found. Finally, the reliability of the device was also investigated. The device with the properties of reversible resistance switching and non-destructive readout is suitable for nonvolatile memory application.
Ferroelectric memory structure and fabrication method thereof
(2006-03-21)
Tseng
;
Tseung-Yuen
;
Lee
;
Shean Yiah
A ferroelectric memory structure is disclosed. The ferroelectric memory structure includes a substrate, an insulating layer formed on the substrate, a plurality of oxide electrodes formed on the insulating layer, a ferroelectric layer formed on the insulating layer and the plurality of oxide electrodes, and a plurality of metallic electrodes formed on the ferroelectric layer and corresponding to the plurality of the oxide electrodes.
On embed-ding cycles into faulty twisted cubes
(2006-03-22)
Yang, MC
;
Li, TK
;
Tan, JJM
;
Hsu, LH
;
資訊工程學系
The twisted cube TQ(n) is an alternative to the popular hypercube network. Recently, some interesting properties of TQ(n) were investigated. In this paper, we study the pancycle problem on faulty twisted cubes. Let f(e) and f(v) be the numbers of faulty edges and faulty vertices in TQ(n), respectively. We show that, with f(e) + f(v) <= n - 2, a faulty TQ(n) still contains a cycle of length l for every 4 <= l < V(TQ(n)) - f(v) and odd integer n >= 3. (C) 2005 Elsevier Inc. All rights reserved.