Browsing by Issue Date, starting with "2010-09-30"

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Temperature dependence of resistance and thermopower of thin indium tin oxide films
(2010-09-30)
Lin, Bo-Tsung
;
Chen, Yi-Fu
;
Lin, Juhn-Jong
;
Wu, Chih-Yuan
;
電子物理學系
We have measured the resistance and thermopower of a series of RF sputtered and annealed indium tin oxide (ITO) thin films from 300 K down to liquid-helium temperatures. Thermal annealing was performed to modulate the levels of disorder (i.e., resistivity) of the samples. The measured resistances are well described by the Bloch-Grilneisen law between 150 and 300 K, suggesting that our thin films are metallic. At lower temperatures, a resistance rise with decreasing temperature was observed, which can be quantitatively ascribed to the two-dimensional electron-electron interaction and weak-localization effects. The thermopowers in all samples are negative and reveal fairly linear temperature dependence over the whole measurement temperature range, strongly indicating free-electron like conduction characteristics in ITO thin films. As a result, the carrier concentration in each film can be reliably determined. This work demonstrates that ITO films as thin as 15 nm thick can already possess high metallic conductivity. (C) 2010 Elsevier B.V. All rights reserved.
High Frequency Flip Chip Package Process of Polymer Substrate and Structure thereof
(2010-09-30)
Chang, Edward-yi
;
Hsu, Li-Han
;
Oil, Chee-Way
;
Wu, Wei-Cheng
;
Wang, Chin-te
In a high frequency flip chip package process of a polymer substrate and a structure thereof, the structure is a one-layer structure packaged by a high frequency flip chip package process to overcome the shortcomings of a conventional two-layer structure packaged by the high frequency flip chip package process. The conventional structure not only incurs additional insertion loss and return loss in its high frequency characteristic, but also brings out a reliability issue. Thus, the manufacturing process of a ceramic substrate in the conventional structure still has the disadvantages of a poor yield rate and a high cost.
Temperature dependence of resistance and thermopower of thin indium tin oxide films
(2010-09-30)
Lin, Bo-Tsung
;
Chen, Yi-Fu
;
Lin, Juhn-Jong
;
Wu, Chih-Yuan
;
電子物理學系
We have measured the resistance and thermopower of a series of RF sputtered and annealed indium tin oxide (ITO) thin films from 300 K down to liquid-helium temperatures. Thermal annealing was performed to modulate the levels of disorder (i.e., resistivity) of the samples. The measured resistances are well described by the Bloch-Grilneisen law between 150 and 300 K, suggesting that our thin films are metallic. At lower temperatures, a resistance rise with decreasing temperature was observed, which can be quantitatively ascribed to the two-dimensional electron-electron interaction and weak-localization effects. The thermopowers in all samples are negative and reveal fairly linear temperature dependence over the whole measurement temperature range, strongly indicating free-electron like conduction characteristics in ITO thin films. As a result, the carrier concentration in each film can be reliably determined. This work demonstrates that ITO films as thin as 15 nm thick can already possess high metallic conductivity. (C) 2010 Elsevier B.V. All rights reserved.
Ultrafast relaxation dynamics of photoexcitations in poly(3-hexylthiophene) for the determination of the defect concentration
(2010-09-30)
Lee, Yu Hsien
;
Yabushita, Atsushi
;
Hsu, Chain Shu
;
Yang, Sheng Hsiung
;
Iwakura, Izumi
Ultrafast pump-probe spectroscopy of poly(3-hexylthiophene) (P3HT) films was performed using a 9-fs laser and a broadband lock-in detection system. The fast geometrical relaxation (GR) time was attributed to the transition from a free exciton (FE) to form a bound polaron pair (BPP), and the time constant was estimated to be tau(GR) = 90 +/- 2 fs. The relaxation time constant of BPP was determined as tau(BPP) = 710 +/- 40 fs. The measurement of pump-power dependence enabled us to distinguish the defect trapping process of BPPs from other parallel decay processes and to determine the defect concentration of a P3HT thin film. (C) 2010 Elsevier B.V. All rights reserved.
Low-power VCO with phase-noise improvement in 0.18 mu m CMOS technology
(2010-09-30)
Liang, C. -P.
;
Huang, T. -J.
;
Rao, P. -Z.
;
Chung, S. -J.
;
傳播研究所
A low-power 5.25 GHz voltage-controlled oscillator ( VCO) with phase-noise improvement is designed in a 0.18 mu m CMOS 1P6M process. Owing to the use of a larger value of parallel capacitor, an additional harmonic-suppressed capacitor, and an appropriate bulk bias voltage of transistor, a good figure of merit of - 190 dBc/Hz can be achieved without extra chip area and CMOS process steps. The fabricated VCO operates from 5.12 to 5.36 GHz with a core power consumption of 1.9 mW and active chip area of 0.15 mm(2). The measured phase noise at 1 MHz offset is about - 119 dBc/Hz.
具電路延遲評估機制之適應性功率控制裝置
(2010-10-01)
謝維致
;
黃威
本發明提供一種具電路延遲評估機制之適應性功率控制裝置，其包含一多模式功率閘網路、一電壓感測器、一可變門檻比較器、一冗餘區間偵測電路以及一雙向位移暫存器，該多模式功率閘網路連接於一電源與一電路模組之間，且該多模式功率閘網路與該電路模組形成一虛擬電壓源，該虛擬電壓源為該電路模組之連接節點，該多模式功率閘網路包含複數個電晶體，其使該多模式功率閘網路依據該冗餘區間偵測電路所判斷之冗餘區間存在狀況而改變該電源輸出至該電路模組之功率。
Authentication and recovery of an image by sharing and lattice-embedding
(2010-10-01)
Lin, Sian-Jheng
;
Lin, Ja-Chen
;
資訊工程學系
;
Department of Computer Science
Based on sharing and lattice-embedding techniques, we present an authentication-recovery method for an image. The recovery data are shared among many shadows, then lattice-embedding is utilized to embed each shadow in the discrete cosine transform domain of an 8x8 block. The proposed method can resist certain content-preserving operations such as JPEG compression, Gaussian noise, and brightness adjustment, up to a tolerance level controlled by a quantization parameter value. The method can also resist certain security attacks such as a cut-and-paste attack, a collage attack, and a vector quantization attack. Compared with previous works, the proposed method has following major advantages and novelty: (1) the method does not require prediction of the tampering trace, and the tampered blocks are always recovered as long as the number of valid blocks reaches a threshold and (2) lattice-embedding yields smaller distortion than does parity-check quantization, and the latter was often used in reported works. (C) 2010 SPIE and IS&T. [DOI: 10.1117/1.3500799]
Structural Effects on Highly Directional Far-Field Emission Patterns of GaN-Based Micro-Cavity Light-Emitting Diodes With Photonic Crystals
(2010-10-01)
Lai, Chun-Feng
;
Kuo, Hao-Chung
;
Chao, Chia-Hsin
;
Yu, Peichen
;
Yeh, Wen-Yung
This study theoretically and experimentally investigates the highly directional far-field emission patterns of GaN photonic crystal (PhC) micro-cavity light-emitting diodes (MCLEDs) depending on varying structural parameters. Angular-spectra-resolved electroluminescence measurements reveals the behavior of guided-mode extraction which is significantly affected by the structural parameters of GaN PhC MCLEDs, where the GaN cavity thickness decides the extracted guided mode numbers, PhC lattice constant influences the distribution of far-field emission, and PhC hole depth affects the interaction with guided modes. The proposed GaN ultrathin MCLED (uMCLED) with PhC lattice constant of 420 nm and deep hole depth of 250 nm exhibited a maximum output light extraction efficiency of 248% under one-watt input power compared to GaN non-PhC uMCLED and produced a directional far-field emission pattern at half intensity near +/- 17 degrees. The present results indicate that highly directional light extraction enhancement could contribute to developments of many applications, especially for etendue-limited applications such as pico-projectors.
Photoresponse of hydrothermally grown lateral ZnO nanowires
(2010-10-01)
Yang, Po-Yu
;
Wang, Jyh-Liang
;
Tsai, Wei-Chih
;
Wang, Shui-Jinn
;
Lin, Jia-Chuan
In this paper, a simple self-assembled lateral growth of ZnO nanowires (NWs) photodetector has been synthesized by a hydrothermal method at a temperature as low as 85 degrees C. The ZnO NWs exhibit single-crystalline wurtzite with elongated c-axis and can be selectively lateral self-assembled around the edges of ZnO seeding layer. The current of ZnO NWs is sensitive to the variation of ambient pressures, i.e. 4.47 mu A was decreased to 1.48 mu A with 5 V-bias as 1.1 x 10(-6) Torr changed to 760 Torr. accordingly. Moreover, the current voltage characteristics of ZnO NWs photodetectors can be evidently distinguished by UV illumination (i.e. lambda = 325 nm). The photocurrent of ZnO NWs with UV illumination is twice larger than dark current while the voltage biased at 5 V. Consequently, this faster photoresponse convinces that the hydrothermally grown lateral ZnO NWs devices have a fairly good for the fabrication of UV photodetectors. (C) 2010 Elsevier B.V. All rights reserved.
高分子基板之高頻覆晶封裝製程及其結構
(2010-10-01)
張翼
;
許立翰
;
胡志偉
;
吳偉誠
;
王景德
本發明係提供一種高分子基板之高頻覆晶封裝製程及其結構，其係利用一階層之高頻覆晶封裝製程所封裝之結構，該結構可有效解決習用經由二階層之高頻覆晶封裝製程所製造之結構，其不僅在高頻特性上會帶來一額外之入射損耗與反射損耗，同時在應用上容易產生一可靠度問題、以及在該習用結構中之一陶瓷基板的製程良率上，仍存在有不佳及成本偏高等缺點。
物件影像偵測方法
(2010-10-01)
韓欽銓
;
陳映濃
本發明揭露一種物件影像偵測方法，其係主要由粗糙至精緻的分析方式以偵測物件影像，此物件影像偵測方法係於採集一影像後，先進行影像的前處理以使得所採集的影像可進行降維與資訊融合，接續，再以已訓練過的過濾器以進行特徵的過濾，最後，則依序利用粗糙層級感知判斷與精緻層級感知判斷以對經過過濾的影像進行進一步類神經網路物件影像偵測以確認此影像之特徵是否符合預先設定之目標物件影像。因此，本發明之物件影像偵測方法係同時利用統計方法、類神經網路方法以及適應性漸進演算法(adaboost)三大主流影像偵測方式來進行物件影像的偵測，以兼顧適應性漸進演算法的快速與類神經網路方法的準確性。
Effect of Al-Trace Width on the Electromigration Failure Time of Flip-Chip Solder Joints
(2010-10-01)
Liang, S. W.
;
Hsiao, H. Y.
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effect of Al-trace width on electromigration (EM) in flip-chip solder joints was investigated experimentally. EM tests were performed on eutectic Sn-Ag solders with 40-mu m- and 100-mu m-wide Al traces. Under the same stressing conditions (0.5 A at 165 degrees C), the failure time was 44.1 h for solder joints with 40-mu m-wide traces and 250.1 h for solder joints with 100-mu m-wide traces. The Al-trace width influenced both the current crowding and the Joule heating effects. Thus, both effects are responsible for the significant difference in failure time. Finite-element analysis was used to examine the current crowding effect in solder bumps with Al traces of the two different widths. The results showed that the current crowding effect was slightly higher in joints with 40-mu m-wide traces. In addition, the temperature coefficient was used to measure the real temperatures in the solder bumps during EM. The results indicated that the width of the Al traces had a substantial influence on the Joule heating effect. The measured temperature in the solder bump was 218.2 degrees C and 172.2 degrees C for the bump with 40-mu m- and 100-mu m-wide Al traces, respectively. This difference in the Joule heating effect plays a crucial role in causing the difference in the failure time of solder joints with the two different widths.
(110)-Exposed Gold Nanocoral Electrode as Low Onset Potential Selective Glucose Sensor
(2010-10-01)
Cheng, Ta-Ming
;
Huang, Ting-Kai
;
Lin, Huang-Kai
;
Tung, Sze-Ping
;
Chen, Yu-Liang
A straightforward electrochemical deposition process was developed to grow gold nanostructures, including nanocoral, nanothorn, branched belt, and nanoparticle, on carbon electrodes by reducing HAuCl(4) under constant potentials in mixtures containing CTAC and/or NaNO(3). Among the nanostructures, the quasi-one-dimensional nanocoral electrode showed the highest surface area. Because of this, it provided excellent electrochemical performances in cyclic voltammetric (CV) studies for kinetic-controlled enzyme-free glucose oxidation reactions. In amperometric studies carried out at 0.200 V in PBS (pH 7.40, 0.100 M), the nanocoral electrode showed the highest anodic current response. It also offered the greatest sensitivity, 22.6 mu AmM(-1)cm(-2), an extended linear range, 5.00 x 10(-2) mM to 3.00 x 10(1) mM, and a low detection limit, 1.00 x 10(1) mu m among the electrodes investigated in this study. In addition, the glucose oxidation by the nanocoral electrode started at -0.280 V. more negative than the one of using a commercial Au electrode as the working electrode. This is attributed to the presence of exposed Au (110) surfaces on the electrode. The feature was applied to oxidize glucose selectively in the presence of ascorbic acid (AA) and uric acid (UA), common interferences found in physiological analytes. With an applied voltage at -0.100 V. the AA oxidation (started at -0.080 V) can be avoided while the glucose oxidation still provides a significant response.
Colour Appearance Shifts in Two Different-Sized Viewing Conditions
(2010-10-01)
Hsieh, Tsuei-Ju
;
Chen, I-Ping
;
應用藝術研究所
;
Institute of Applied Arts
This study assessed the effect of size on colour appearance, using a colour matching paradigm where two sizes were presented in a setting similar to a normal colour selection interface. Twelve colours sampling the entire range of the colour spectrum were chosen as target stimuli. The target stimuli consisted of either a large (30 degrees by 50 degrees) or a small (0.5 degrees by 0.5 degrees) test field displayed on a cathode ray tube (CRT). In the experiment, a set of small colour samples consisting of the target and its neighboring colours was presented on the screen. Fifty-seven participants were asked to pick a colour from the sample set that appeared to exactly match the target. Results in CIECAM02 showed a consistent increase in the apparent brightness (Q) but some decrease in saturation (s) for the larger field. Hue shifts were observed to form a systematic pattern. We noticed a discernable trend showing that, for targets of bluish or purplish colour hues, the accuracy of colour matching is lower and colour difference is greater in the condition of the large viewing field. (C) 2010 Wiley Periodicals, Inc. Col Res Appl, 35, 352-360, 2010; Published online 17 June 2010 in Wiley Inter Science (www.interscience.wiley.com). DOT 10.1002/col.20580
Formation and Structural Characterization of Cobalt Titanate Thin Films
(2010-10-01)
Chuang, Shiow-Huey
;
Gao, Reui-Hong
;
Gao, Kuo-Hsing
;
Chiang, Michael Y.
;
Chao, Tien-Sheng
This research successfully produces high quality cobalt titanate (CoTiO(3)) thin films, a high-k material for gate dielectrics, on SiO(2)/Si(100) substrates via a spin-coating method with a sol-like precursor solution. This study prepares the precursor solution by reactions of cobalt acetate and titanium isopropoxide in 2-methoxyethanol. The current work obtains CoTiO(3) thin films after spin coating followed by post-treatment with air under 550 similar to 650 degrees C. A scanning electron microscope, determines film thickness and morphology and X-ray diffraction identifies material structures. This study uses X-ray photoelectron spectroscopy to analyze both elemental compositions and chemical bonding characters of the thin films. This work also investigates reaction pathways.
A Collection of Special Efforts on DSSC in 2009 Preface
(2010-10-01)
Wang, Hong-Wen
;
Diau, Eric Wei-Guang
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應用化學系
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應用化學系分子科學碩博班
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Department of Applied Chemistry
Probing the onset of strong localization and electron-electron interactions with the presence of a direct insulator-quantum Hall transition
(2010-10-01)
Lo, Shun-Tsung
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Chen, Kuang Yao
;
Lin, T. L.
;
Lin, Li-Hung
;
Luo, Dong-Sheng
We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall transition on increasing the perpendicular magnetic field. However, such a transition does not correspond to the onset of strong localization. The temperature dependences of the Hall resistivity and Hall conductivity reveal the importance of the electron-electron interaction effects for the observed transition in our study. (C) 2010 Elsevier Ltd. All rights reserved.
Wavelength-selectable single-longitudinal-mode Fabry-Perot laser source using inter-injection mode-locked technique
(2010-10-01)
Yeh, Chien-Hung
;
Chow, Chi-Wai
;
光電工程學系
;
Department of Photonics
In this paper, a simple fiber coupled laser configuration to generate stable and tunable single-longitudinal-mode (SLM) optical output based on a pair of Fabry-Perot laser diode (FP-LD) using inter-injection operation is proposed and experimentally demonstrated. By adjusting the tunable filter inside the laser cavity to align the corresponding mode of the FP-LDs, the lasing wavelength can be tuned in the wavelength range of 1528.6-1562.2 nm with 1.4 nm tuning step. In addition, the output performance of the proposed fiber coupled laser has also been discussed. (c) 2010 Elsevier Inc. All rights reserved.
Numerical Simulation of Moving Contact Lines with Surfactant by Immersed Boundary Method
(2010-10-01)
Lai, Ming-Chih
;
Tseng, Yu-Hau
;
Huang, Huaxiong
;
應用數學系
;
Department of Applied Mathematics
In this paper, we present an immersed boundary method for simulating moving contact lines with surfactant. The governing equations are the incompressible Navier-Stokes equations with the usual mixture of Eulerian fluid variables and Lagrangian interfacial markers. The immersed boundary force has two components: one from the nonhomogeneous surface tension determined by the distribution of surfactant along the fluid interface, and the other from unbalanced Young's force at the moving contact lines. An artificial tangential velocity has been added to the Lagrangian markers to ensure that the markers are uniformly distributed at all times. The corresponding modified surfactant equation is solved in a way such that the total surfactant mass is conserved. Numerical experiments including convergence analysis are carefully conducted. The effect of the surfactant on the motion of hydrophilic and hydrophobic drops are investigated in detail.
Dibenzo[f,h]thieno[3,4-b] quinoxaline-fullerene heterojunction bilayer solar cells with complementary spectrum coverage
(2010-10-01)
Kekuda, Dhananjaya
;
Huang, Jen-Shien
;
Velusamy, Marappan
;
Lin, Jiann T.
;
Chu, Chih-Wei
In the present article, potential of a bilayer organic solar cell has been investigated. We utilize newly synthesized small molecules, namely dibenzo[f,h]thieno[3,4-b]quinoxaline as electron donors for solar cells in heterojunction bilayer configuration. These small molecules with a narrow absorption band in the range 400-450 nm provide a complementary spectrum for the fullerene C(70), thereby leading to an overall power conversion efficiency of 2.6 +/- 0.2% under 100 mW/cm(2) incident radiation. Thermal annealing seems to impact the charge separation at the donor-acceptor interface, which eventually affects device performance. This work demonstrates that carefully optimized bilayer devices are comparable to the bulk heterojunction counterparts. (C) 2010 Elsevier B.V. All rights reserved.