Browsing by Issue Date, starting with "2006-02-13"

Now showing 1 - 20 of 63692

Nanoimprinting-lithography-induced self-aligned liquid crystals for novel multifunctional optical films
(2006-02-13)
Chiu, CH
;
Kuo, HL
;
Chen, PC
;
Wen, CH
;
Liu, YC
Polymerizable nematic liquid crystal (LC) was adopted as a resist for our newly developed nanoimprinting lithography process. Liquid crystal molecules were self-aligned during imprinting process without precoated alignment layer. The large patterned area was able to achieve 4x4 cm(2) at very low impriting pressure, 1.5 bar. The optical anisotropic was verified through polarized optical microscopy and the retardation was measured by polarized ultraviolet/visible spectrometer. The micrograted LC films prepared by this novel method offer the potential applications for a LC alignment layer within LC cells, as well as preparation of optical anisotropic films. (c) 2006 American Institute of Physics.
Orbital susceptibilities of PbSe quantum dots
(2006-02-14)
Jian, WB
;
Lu, WG
;
Fang, JY
;
Chiang, SJ
;
Lan, MD
Different sizes of three-dimensional PbSe quantum dots have been synthesized for the study of orbital magnetic susceptibilities. Two types of orbital susceptibilities have been found, including the Curie susceptibility and finite-size corrections to the Landau susceptibility. The Curie term of a quantum dot manifests itself in the temperature dependence of magnetic susceptibility at low temperatures, while the field dependence of differential susceptibility at high temperatures shows finite-size corrections to the Landau susceptibility. Both of the two kinds of orbital susceptibility, estimated per quantum dot, show linear dependence on the size. (c) 2006 American Institute of Physics.
Nanomechanical characterizations of InGaN thin films
(2006-02-15)
Jian, SR
;
Fang, TH
;
Chuu, DS
;
電子物理學系
;
Department of Electrophysics
InxGa1-x thin films with In concentration ranging from 25 to 34 at.% were deposited on sapphire substrate by metal-organic chemical vapor deposition (MOCVD). Crystalline structure and surface morphology of the deposited films were studied by using X-ray diffraction (XRD) and atomic force microscopy (AFM). Hardness, Young's modulus and creep resistance were measured using a nanoindenter. Among the deposited films, In0.25Ga0.75N film exhibits a larger grain size and a higher surface roughness. Results indicate that hardness decreases slightly with increasing In concentration in the InxGa1-xN films ranged from 16.6 +/- 1.1 to 16.1 +/- 0.7 GPa and, Young's modulus for the In0.25Ga0.75N, In0.3Ga0.7N and In0.34Ga0.66N films are 375.8 +/- 23.1, 322.4 +/- 13.5 and 373.9 +/- 28.6 GPa, respectively. In addition, the time-dependent nanoindentation creep experiments are presented in this article. (c) 2005 Elsevier B.V. All rights reserved.
Impact of band gap shrinkage on simulated bifurcation routes in directly modulated semiconductor lasers
(2006-02-15)
Lim, CG
;
Iezekiel, S
;
Snowden, CM
;
光電工程學系
;
Department of Photonics
A carrier heating model is derived by taking into account the various temperature processes in the active layer of laser diodes. This model is then used to simulate the static and dynamic characteristics of a directly modulated 1.55 mu m distributed-feedback laser diode. The calculated results are compared with the measured results of this device as obtained in an earlier work [H. F. Liu and W. F. Ngal, IEEE J. Quantum Electron. 29, 1668 (1993)], and this reveals the significant impact of band gap shrinkage on simulated results. This study also shows that the carrier heating model is a self-consistent model that naturally describes the gain suppression phenomena in directly modulated laser diodes. (c) 2006 American Institute of Physics.
Short time deposition kinetics of diethyl phthalate and dibutyl phthalate on a silicon wafer surface
(2006-02-15)
Kang, YH
;
Den, W
;
Bai, HL
;
環境工程研究所
;
Institute of Environmental Engineering
Short time adsorption and desorption behaviors of two alkyl phthalate esters, namely diethyl phthalate (DEP) and dibutyl phthalate (DBP), on silicon wafers exposed under various ambient concentrations were experimentally and theoretically investigated. The results showed that the surface density of DBP was significantly affected by both the length of exposure time and its ambient concentration, whereas that of DEP was only affected by its ambient concentration within the tested periods between 60 and 240 min. The determination of rate parameters for adsorption and desorption showed that the rate constants of DEP were always larger than those of DBP. Also, the sticking coefficient of DEP was larger during the initial adsorption stage due to its relatively lower molecular weight as compared to DBP. The value of the sticking coefficient for DEP, however, decreased much faster such that the value eventually became smaller than that for DBP. Therefore, for silicon wafers experiencing a short exposure time, organic compounds with lower molecular weights may be a more important source of airborne molecular contamination than those with higher molecular weights.
Continuous time Markov chains observed on an alternating renewal process with exponentially distributed durations
(2006-02-15)
Chan, WY
;
Peng, NF
;
統計學研究所
;
Institute of Statistics
A continuous time Markov chain observed on a system following the dynamic behavior of an alternating renewal process is studied. This alternating renewal process is assumed to have exponentially distributed durations. The limiting behavior of the process is examined. Examples of applications are given. (c) 2005 Published by Elsevier B.V.
影子
(2006-02-15)
管管
Inelastic interactions of electrons with cylindrical interfaces
(2006-02-15)
Tu, YH
;
Kwei, CM
;
Tung, CJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A theory was developed to deal with inelastic interactions for an electron moving parallel to the axis of a cylindrical structure. Formulas for the differential inverse inelastic mean free path (DIIMFP) and the total inverse inelastic mean free path (IIMFP) were derived using dielectric response theory. A sum-rule-constrained extended Drude dielectric function with spatial dispersion was applied to calculate DIIMFPs and IIMFPs for a solid wire and a cavity in solid. The calculated results showed that surface excitations occurred as the electron moved near the boundary either inside or outside the solid, whereas volume excitations arose only for electron moving inside the solid. It was found that the probability for surface excitations increases and that for volume excitations decreases for an electron moving close to the surface. Near the surface, the decrease in volume excitations is compensated by the increase in surface excitations. For a cavity in solid, the IIMFP inside the solid can be approximated by a constant value equal to the IIMFP for the infinite solid, except in the immediate vicinity of the cavity boundary. (c) 2005 Elsevier B.V. All rights reserved.
Series quartz crystal sensor for remote bacteria population monitoring in raw milk via the Internet
(2006-02-15)
Chang, KS
;
Jang, HD
;
Lee, CF
;
Lee, YG
;
Yuan, CJ
A remote monitoring system based on a piezoelectric quartz crystal (SPQC) sensor was developed for the determination of the bacteria population in raw milk. The system employs the Windows XP server operating system, and its programs for data acquisition, display and transmission were developed using the LabVIEW 7.1 programming language. The circuit design consists of a circuit with a piezoelectric quartz crystal (SPQC) and a pair of electrodes. This system can provide dynamic data monitoring on a web-page via the Internet. Immersion of the electrodes in a cell culture with bacteria inoculums resulted in a change of frequency caused by the impedance change due to microbial metabolism and the adherence of bacteria on the surface of the electrodes. The calibration curve of detection times against density of bacteria showed a linear correlation coefficient (R-2 = 0.9165) over the range of 70-10(6) CFU ml(-1). The sensor could acquire sufficient data rapidly (within 4 h) and thus enabled real-time monitoring of bacteria growth via the Internet. This system has potential application in the detection of bacteria concentration of milk at dairy farms. (c) 2005 Elsevier B.V. All rights reserved.
Hydrogen bonding interactions and miscibility between phenolic resin and octa(acetoxystyryl) polyhedral oligomeric silsesquioxane (AS-POSS) nanocomposites
(2006-02-15)
Kuo, SW
;
Lin, HC
;
Huang, WJ
;
Huang, CF
;
Chang, FC
We have synthesized a polyhedral oligomeric silisesquioxane (POSS) derivative containing eight acetoxystyryl functional groups [octa(acetoxystyryl)octasilsesquioxane (AS-POSS)] and then blended it with phenolic resin to form nanocomposites stabilized through hydrogen bonding interactions between the phenolic resin's hydroxyl group and the AS-POSS derivative's carbonyl and siloxane groups. One-and two-dimensional infrared spectroscopy analyses provided positive evidence for these types of hydrogen bonding interactions. In addition, we calculated the interassociation equilibrium constant, based on the Painter-Coleman association model (PCAM), between phenolic resin and POSS indirectly from the fraction of hydrogen-bonded carbonyl groups; quantitative analyses indicate that the hydroxyl-siloxane interassociation from the PCAM is entirely consistent with the classical Coggesthall and Saier (C and S) methodology. From a thermal analysis, we observed that the miscibility between phenolic and AS-POSS occurs at a relatively low AS-POSS content, which characterizes this mixture as a polymer nanocomposite system. (c) 2006 Wiley Periodicals, Inc.
製作自行聚合奈米粒之方法
(2006-02-16)
陳衛國
;
李明知
;
周武清
;
陳文雄
;
柯文政
一種用以成長奈米粒的方法，係可在任何晶格匹配度材料之緩衝層上，不需透過圖案遮罩(mask)之製作，即可自行聚合方式(self–assembled)成長包含III–V族、II–VI族或IV–IV族材料之二元、三元以上化合物之奈米粒為特徵。該方法係在基板上先成長任一種材料之緩衝層，然後於適當溫度範圍內完成週期性流量調制磊晶成長，包含：在通入第二反應物前，先通入清除氣體並調制第一反應物至較低第一莫耳流量範圍，致使通入之第二反應物得以在緩衝層上形成金屬或該高金屬含量化合物島狀物，再通入清除氣體以清除殘餘未形成金屬或高金屬含量化合物島狀物之第二反應物，再調制第一反應物至較高第二莫耳流量範圍使該金屬或該高金屬含量化合物島狀物可以形成奈米粒。最後在完成週期性流量調制磊晶成長後，於較高之成長溫度下進行再結晶化步驟，以形成結構性佳之高品質奈米粒。
以液相沈積成長二氧化鉿薄膜之方法
(2006-02-16)
蕭智文
;
羅正忠
;
陳昶維
本發明關於利用液相沉積法以成長具有高介電常數之絕緣膜，特別是二氧化鉿絕緣層之方法，包括：(a)將二氧化鉿(HfO2)粉末加入氫氟酸(HF)溶液中，形成氫氟鉿酸鹽(HxHfyFz)溶液，前於低溫下加以攪拌溶解，使成為飽和溶液；(b)加入去離子水於該飽和溶液中，使其成為過飽和溶液；(c)將矽基板置入該過飽和溶液中，由於化學逆反應，可沉積高介電常數二氧化鉿(HfO2)薄膜於該矽基板上。
保護銲錫接點之方法及可降低銲錫接點中電遷移及焦耳熱效應之構造
(2006-02-16)
陳智
;
葉長青
;
杜經寧
本發明提供一種保護銲錫接點之方法，包括於基板與晶片之銲錫接點上，製作金屬墊，然後再製作連接基板與晶片之凸塊，其中該金屬墊層(UBM或Pad metallurgy)與晶片或基板連接之端點位置上，被加入一高電阻率之材料以均化凸塊之電子流分布，而可降低電遷移、焦耳熱效應升溫現象。
遞減面積之分散式靜電放電防護電路
(2006-02-16)
柯明道
;
郭秉捷
本發明提出一種遞減面積之分散式靜電放電防護電路，包括一信號輸入端、一接地端、一信號輸出端，且有一電源供應端，並有數靜電放電防護元件組相並聯在信號輸入端及信號輸出端間，且每一靜電放電防護元件組連接於電源供應端及接地端間，且在信號輸入端及信號輸出端間串聯有數高阻抗傳輸線，且每一高阻抗傳輸線分別連接於信號輸入端、靜電放電防護元件組及信號輸出端間，其特徵在於：每一靜電放電防護元件組包含二靜電放電防護元件，且靜電放電防護元件組內之靜電放電防護元件的面積尺寸係由信號輸入端至信號輸出端呈現遞減順序。本發明兼具寬頻電路及阻抗匹配之特點，並具較佳之靜電放電防護效果。
Effect of the transition metal on the synthesis of quaternary sulfides MPb8In17S34 (M = Cu, Ag, Au)
(2006-02-20)
Wang, KC
;
Lee, CS
;
應用化學系
;
Department of Applied Chemistry
Quaternary sulfides MPb8In17S34 (M = Cu, Ag, Au) were synthesized at 1123 K from their elements in stoichiometric ratios. These compounds crystallize in monoclinic space group P2(1)/m. The crystal structures feature combinations of (2)(infinity)[InS2] (NaCl111-type) and (2)(infinity)[MPb2In3S6] (NaCl100-type) slabs. These compounds are semiconductors with band gaps near 1.3 eV.
A new yellow fluorescent dopant for high-efficiency organic light-emitting devices
(2006-02-21)
Wu, YS
;
Liu, TH
;
Chen, HH
;
Chen, CH
;
應用化學系
We describe the design and synthesis of a sterically hindered yellow dopant, tetra(l-butyl)rubrene (TBRb) which, when doped in either 1,4-bis[N-(1-naphthyl)-N'-phenylamino]-biphenyl or aluminum tris(8-hydroxyquinoline) (Alq(3)) as emitter, shows nearly 25% increase in luminance efficiency over that of the state-of-the-art rubrene (Rb) device without significantly effecting its corresponding color. At 5% doping in Alq3 and 20 mA/cm(2) current drive condition, the electroluminescence efficiency of TBRb reaches 8.5 cd/A and 2.8 1m/W with a yellow color of Commission Internationale de l'Eclairage chromaticity coordinates (CIEx,y)=[0.52,0.48], which is among the best ever reported for yellow electrofluorescence in organic light-emitting devices. (c) 2005 Elsevier B.V. All rights reserved.
Microelectro mechanical system for magneto-optic data storage apparatus
(2006-02-21)
Hsu
;
Wensyang
;
Shieh
;
Han-Ping
;
Sun
The present invention relates to a Microelectro mechanical system structure. More specifically the invention relates to utilize a sacrificial layer to fabricate an air bearing structure, followed by forming an aperture, and reducing the aperture to nano-scale by electroplating. And then, by using of two thick film photoresist films for twice electroplating fabrication, for fabricate metal microcoils having high aspect ratio structure and interconnection metal line, to achieve efficiencies of utilizing area and reducing resistance. Moreover, proceed lithography depends on different portions and exposure dose. Then form a single photoresist film to have a specific dimension and thickness structure, finally, by using reflow process, forming a magneto-optic (MO) pickup head comprises of Supersphere Solid Immersion Lens (SSIL), nano-aperture, microcoils and air bearing by using an integrated fabrication, with advantages such as no high cost device and precise apparatus are required in the process of fabrication, mass production in batch fabrication, without step of assembly, for high-density data storage and rewritable record.
電荷幫浦式直流轉直流轉換器增益電路
(2006-02-21)
張隆國
;
胡致暉
本發明係為藉由電荷幫浦輸出級跨壓損失修正電路(PGI)，使輸出級的切換開關能適當的阻止輸出端的電荷倒灌回升壓電路中，並且不會產生輸出級的跨壓損失，改善輸出電壓的限制，且可搭配一比較器與一緩衝電路形成ni指數倍率升壓的直流轉直流電源轉換電路，簡化本發明之整體的升壓電路，可減少製作成本，適用於低輸入電壓(如：一般電池)的情沉下操作，可作為直流轉直流的電壓轉換器。
Solar-pumped active device
(2006-02-23)
Chi, Sien
;
Chen, Nan-Kuang
;
Shy, Jow-Tsong
The present invention provides a solar-pumped active device which utilizes a holographic antenna grating on a solar energy silicon substrate to select specific diffracted wavelength and couple pump wavelength in an approximately vertical way and converge the pump wavelength to excite an optical gain medium so that an optical amplifier or a laser can be obtained. The present invention requires no big size and is flexible over the surface shape and is suitable for free space optical communications on the ground and satellite optical communications. It means that the holographic antenna grating can be applied on the top floor of a building or on the glass surface of an outer wall. If it is applied to a satellite, the present invention can be deposited on a solar energy cell substrate to form a high optical amplification so that not only the electricity required in satellite optical communications can be reduced, but also a high-speed and large capacity of data can be transferred between satellites.
Effect of deposition temperature and oxygen flow rate on properties of low dielectric constant SiCOH film prepared by plasma enhanced chemical vapor deposition using diethoxymethylsilane
(2006-02-24)
Cheng, YL
;
Wang, YL
;
Hwang, GJ
;
O'Neill, ML
;
Karwacki, EJ
Low dielectric constant (Low-k) films (SiCOH) were deposited from diethoxymethylsiliane [DEMS; SiH(CH3) (OC2H5)(2)] which has two ethoxy groups along with one methyl group attached to the silicon atoms. The deposited films have been characterized for different oxygen flows, ranging from 50 to 250 standard cubic centimeters per minute (seem). The growth rate is increased with the increasing oxygen (O-2) flow. The absorbance spectrum of Fourier transform infrared spectroscopy shows that the frequency of Si-O stretching vibration mode in the SiCOH film is shifted to a higher wave number with the increase of oxygen flow. It is deduced that the oxygen does not participate in a simple oxidative mechanism, and has no apparent impact on the methyl content even if the relative Si-O content of the deposited films is up to an O-2/DEMS flow rate ratio of 1:1. Also, the refractive index is decreased with increasing the oxygen flow and slightly increased with the deposition temperature. The dielectric constant of the SiCOH is investigated between 2.7 and 3.2, depending on the deposition temperature and O-2/DEMS flow rate ratio, which is lower than that of the current OSG films (k=2.9-3.3). SiCOH films deposited with DEMS only exhibit higher mechanical hardness and lower leakage current than those deposited with both DEMS and oxygen. (c) 2005 Elsevier B.V. All rights reserved.