Browsing by Issue Date, starting with "2013-06-21"

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Quantum-interference transport through surface layers of indium-doped ZnO nanowires
(2013-06-21)
Chiu, Shao-Pin
;
Lu, Jia Grace
;
Lin, Juhn-Jong
;
電子物理學系
;
物理研究所
We have fabricated indium-doped ZnO (IZO) nanowires (NWs) and carried out four-probe electrical-transport measurements on two individual NWs with geometric diameters of approximate to 70 and approximate to 90 nm in a wide temperature T interval of 1-70 K. The NWs reveal overall charge conduction behavior characteristic of disordered metals. In addition to the T dependence of resistance R, we have measured the magnetoresistance (MR) in magnetic fields applied either perpendicular or parallel to the NW axis. Our R(T) and MR data in different T intervals are consistent with the theoretical predictions of the one- (1D), two- (2D) or three-dimensional (3D) weak-localization (WL) and the electron-electron interaction (EEI) effects. In particular, a few dimensionality crossovers in the two effects are observed. These crossover phenomena are consistent with the model of a 'core-shell-like structure' in individual IZO NWs, where an outer shell of thickness t (similar or equal to 15-17 nm) is responsible for the quantum-interference transport. In the WL effect, as the electron dephasing length L-phi gradually decreases with increasing T from the lowest measurement temperatures, a 1D-to-2D dimensionality crossover takes place around a characteristic temperature where L-phi approximately equals d, an effective NW diameter which is slightly smaller than the geometric diameter. As T further increases, a 2D-to-3D dimensionality crossover occurs around another characteristic temperature where L-phi approximately equals t (
應用於晶片封裝與電路板共同設計之晶片接腳指定設計方法及其程式產品
(2013-06-21)
李仁傑
;
陳宏明
一種應用於晶片封裝與電路板共同設計之晶片接腳指定設計方法，其步驟包含接受設定接腳規格與需求、產生複數個接腳圖塊、接腳模塊的建構與群組化及接腳模塊的平面位置配置；其中，依據規格與需求產生各接腳圖塊，而接腳模塊與電路板的組件之配置位置對應，並且每一接腳模塊包含一種接腳圖塊以及一電源接腳模塊，各接腳模塊繞設於該晶片之四個邊，並透過群組化及平面位置再配置之過程，進行封裝面積的最佳化。
Specific heat capacity of molten salt-based alumina nanofluid
(2013-06-21)
Lu, Ming-Chang
;
Huang, Chien-Hsun
;
機械工程學系
;
Department of Mechanical Engineering
There is no consensus on the effect of nanoparticle (NP) addition on the specific heat capacity (SHC) of fluids. In addition, the predictions from the existing model have a large discrepancy from the measured SHCs in nanofluids. We show that the SHC of the molten salt-based alumina nanofluid decreases with reducing particle size and increasing particle concentration. The NP size-dependent SHC is resulted from an augmentation of the nanolayer effect as particle size reduces. A model considering the nanolayer effect which supports the experimental results was proposed.
Homogeneous anisotropic solutions of topologically massive gravity with a cosmological constant and their homogeneous deformations
(2013-06-21)
Moutsopoulos, George
;
電子物理學系
;
Department of Electrophysics
We solve the equations of topologically massive gravity (TMG) with a potentially non-vanishing cosmological constant for homogeneous metrics without isotropy. We only reproduce known solutions. We also discuss their homogeneous deformations, possibly with isotropy. We show that de Sitter space and hyperbolic space cannot be infinitesimally homogeneously deformed in TMG. We clarify some of their Segre-Petrov types and discuss the warped de Sitter spacetime.
Nonequilibrium quantum transport through a dissipative resonant level
(2013-06-21)
Chung, Chung-Hou
;
Le Hur, Karyn
;
Finkelstein, Gleb
;
Vojta, Matthias
;
Woelfle, Peter
The resonant-level model represents a paradigmatic quantum system which serves as a basis for many other quantum impurity models. We provide a comprehensive analysis of the nonequilibrium transport near a quantum phase transition in a spinless dissipative resonant-level model, extending earlier work [Phys. Rev. Lett 102, 216803 (2009)]. A detailed derivation of a rigorous mapping of our system onto an effective Kondo model is presented. A controlled energy-dependent renormalization-group approach is applied to compute the nonequilibrium current in the presence of a finite bias voltage V. In the linear-response regime V -> 0, the system exhibits as a function of the dissipative strength a localized-delocalized quantum transition of the Kosterlitz-Thouless (KT) type. We address fundamental issues of the nonequilibrium transport near the quantum phase transition: Does the bias voltage play the same role as temperature to smear out the transition? What is the scaling of the nonequilibrium conductance near the transition? At finite temperatures, we show that the conductance follows the equilibrium scaling for V < T, while it obeys a distinct nonequilibrium profile for V > T. We furthermore provide different signatures of the transition in the finite-frequency current noise and ac conductance via a recently developed functional renormalization group (FRG) approach. The generalization of our analysis to nonequilibrium transport through a resonant level coupled to two chiral Luttinger liquid leads, generated by fractional quantum Hall edge states, is discussed. Our work on the dissipative resonant level has direct relevance to experiments on a quantum dot coupled to a resistive environment, such as H. Mebrahtu et al., [Nature (London) 488, 61 (2012)].
Performance and characteristics of double layer porous silicon oxide resistance random access memory
(2013-06-24)
Tsai, Tsung-Ming
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Chang, Kuan-Chang
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Zhang, Rui
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Chang, Ting-Chang
;
Lou, J. C.
A bilayer resistive switching memory device with an inserted porous silicon oxide layer is investigated in this letter. Compared with single Zr:SiOx layer structure, Zr: SiOx/ porous SiOx structure outperforms from various aspects, including low operating voltages, tighter distributions of set voltage, higher stability of both low resistance state and high resistance state, and satisfactory endurance characteristics. Electric field simulation by COMSOL (TM) Multiphysics is applied, which corroborates that intensive electric field around the pore in porous SiOx layer guides the conduction of electrons. The constraint of conduction path leads to better stabilization and prominent performance of bilayer resistive switching devices. (C) 2013 AIP Publishing LLC.
Using nanopillars of silicon oxide as a versatile platform for visualizing a selective immunosorbent
(2013-06-24)
Chen, Jem-Kun
;
Zhou, Gang-Yan
;
Huang, Chih-Feng
;
Ko, Fu-Hsiang
;
應用化學系
In this study, we fabricated nanopillar arrays of silicon oxide for use as two-dimensional periodic relief gratings (2DPRGs) on Si surfaces. We deposited antibodies onto the pillar surfaces of 2DPRGs modified with protein G to obtain optical detectors that were specific for the targeted antigen; the antigen units that filled the spaces between the nanopillars of the 2DPRG lead to a dramatic change in the pillar scale. The effective refractive index (n(eff)) of the 2DPRGs was related to the pillar scale of the 2DPRG; after coupling of the antigen, a color change from pure green to orange was observable. (C) 2013 AIP Publishing LLC.
Insertion of a Si layer to reduce operation current for resistive random access memory applications
(2013-06-24)
Chen, Yu-Ting
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Chang, Ting-Chang
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Peng, Han-Kuang
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Tseng, Hsueh-Chih
;
Huang, Jheng-Jie
In this study, a reduction of low resistive state (LRS) current is discovered in a V:SiO2/Si bi-layer structure with the addition of a Si layer. A Pt/V:SiO2/TiN structure is fabricated as the standard sample. The results of conduction mechanism analyses for LRS indicate that a SiO2 interfacial layer forms through oxidation of the inserted Si layer after the set process. The LRS current reduction can be attributed to the formation of this SiO2 layer. In addition, self-compliance behavior for the bi-layer structure during the set process further proves the existence of this SiO2 buffer layer in LRS. (C) 2013 AIP Publishing LLC.
Development of physical-parameter identification procedure for in-situ buildings with sliding-type isolation system
(2013-06-24)
Huang, Ming-Chih
;
Wang, Yen-Po
;
Lin, Tzu-Kang
;
Chen, Yi-Hsuan
;
土木工程學系
A system identification procedure is developed to identify the physical parameters of structures with seismic isolation using the friction pendulum systems (FPSs). The superstructure is assumed to be linear on account of substantial reduction of seismic forces with the installation of FPS. Hysteretic models of both Coulomb's and Mokha's friction mechanism have been considered for the FPS. Simulation results indicate that the physical parameters of the FPS and superstructure can be successfully identified by the proposed scheme. Experimental verification has been conducted further via shaking table tests using realistic earthquake scenarios. The identified parameters from seismic response data indicate that the FPSs behave in better agreement with Mokha's friction mechanism than Coulomb's. Feasibility of the proposed scheme in the identification of FPS-isolated structures using seismic data has been verified. This may facilitate in-situ performance assessment of structures isolated with sliding-type isolation systems. (C) 2013 Elsevier Ltd. All rights reserved.
Method for fabricating a resistor for a resistance random access memory
(2013-06-25)
Tseng Tseung-Yuen
;
Wang Sheng-Yu
;
Tsai Chen-Han
A method for fabricating a resistor for a resistance random access memory (RRAM) includes: (a) forming a first electrode over a substrate; (b) forming a variable resistance layer of zirconium oxide on the first electrode under a working temperature, which ranges from 175° C. to 225° C.; and (c) forming a second electrode of Ti on the variable resistance layer.
Structural and nanomechanical properties of BiFeO3 thin films deposited by radio frequency magnetron sputtering
(2013-06-25)
Jian, Sheng-Rui
;
Chang, Huang-Wei
;
Tseng, Yu-Chin
;
Chen, Ping-Han
;
Juang, Jenh-Yih
The nanomechanical properties of BiFeO3 (BFO) thin films are subjected to nanoindentation evaluation. BFO thin films are grown on the Pt/Ti/SiO2/Si substrates by using radio frequency magnetron sputtering with various deposition temperatures. The structure was analyzed by X-ray diffraction, and the results confirmed the presence of BFO phases. Atomic force microscopy revealed that the average film surface roughness increased with increasing of the deposition temperature. A Berkovich nanoindenter operated with the continuous contact stiffness measurement option indicated that the hardness decreases from 10.6 to 6.8 GPa for films deposited at 350A degrees C and 450A degrees C, respectively. In contrast, Young's modulus for the former is 170.8 GPa as compared to a value of 131.4 GPa for the latter. The relationship between the hardness and film grain size appears to follow closely with the Hall-Petch equation.
Abdominal breathing training apparatus, abdominal breathing training system and method thereof
(2013-06-25)
Hsiao Tzu-Chien
;
Hsu Ru-Shin
;
Hsieh Dai-Ling
An abdominal breathing training apparatus, an abdominal breathing training system and the method thereof are provided. The abdominal breathing training apparatus is adapted for training a trainee how to perform an abdominal breathing and includes a trainer unit, a sensor unit, a data acquisition and conversion unit and a display unit. The trainer unit generates training waveforms and indications. The sensor unit directly measures abdominal movement signals from the trainee, and is positioned adjacent to the abdominal portion of the trainee. The data acquisition and conversion unit is coupled to the sensor unit and generates a trainee abdominal movement waveform according to the measured abdominal movement signals of the trainee. The display unit is coupled to the trainer unit, and displays the training waveforms and the indications to the trainee, who follows the training waveforms on the display unit to perform the abdominal breathing.
Feedback control method and device using the same
(2013-06-25)
Chang Chia-Chi
;
Hsiao Tzu-Chien
The present invention provides a method for feedback control and a device using the same, wherein the device comprising a sensing layer for generating a plurality of sensing signals with respect to the at least one kind of characteristics on the sensing layer, and a driving layer for changing the surface status of the sensing layer. The control method is started a step of acquiring the plurality of sensing signals within a first specific time interval and establishing a first prediction model accordingly, then predicting a distribution status with respect to the at least one kind of characteristic on the sensing layer at a specific time point according to the first prediction model, and finally, determining whether to change the surface status of the sensing layer according to the distribution status.
Formation of Nanostructured Fullerene Interlayer through Accelerated Self-Assembly and Cross-Linking of Trichlorosilane Moieties Leading to Enhanced Efficiency of Photovoltaic Cells
(2013-06-25)
Liang, Wei-Wei
;
Chang, Chih-Yu
;
Lai, Yu-Ying
;
Cheng, Sheng-Wen
;
Chang, Huan-Hsuan
A new cross-linkable fullerene material, bis(2-(trichlorosilyl)propyl)-malonate C-60 (TSMC), functionalized with two trichlorosilane groups, was easily synthesized by Pt-catalyzed olefin hydrosilylation. By making use of facile hydrolysis of the trichlorosilyl moieties, TSMC can be spontaneously self-assembled and cross-linked on the TiOx surface by a simple spin-coating processing without the aid of photoirradiation or post-thermal treatments. The rapid formation of self-assembled and crosslinked TSMC (SA-C-TSMC) effectively passivates the residual hydroxyl groups on the TiOx surface. More significantly, the solvent-resistant TSMC network features a nanostructured surface to provide extra charge-generating interfacial area and straight electron transport pathways. The device (ITO/TiOx/SA-C-TSMC/P3HT:PC61BM (1:1, w/w)/PEDOT:PSS/Ag) with this C-60 interlayer exhibited an efficiency of 3.9% which greatly outperformed the device without this layer. Furthermore, the strategy can also be effectively applied to the device (ITO/TiOx/PDITTDTBT:PC71BM(1:4, w/w)/MoOx/Ag) incorporating a conjugated polymer, poly(diindenothiophene-alt-dithienylbenzothiadizole) copolymer (PDITTDTBT). This device delivered a high efficiency of 5.8% which represents a 35% enhancement over the device without SA-C-TSMC. This new generation of trichlorosilane-based fullerene offers an easy and accelerated processing technique to produce efficient and cost-effective inverted solar cells.
Ferroelectric Control of the Conduction at the LaAlO3/SrTiO3 Heterointerface
(2013-06-25)
Vu Thanh Tra
;
Chen, Jhih-Wei
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Huang, Po-Cheng
;
Huang, Bo-Chao
;
Cao, Ye
Photo-crosslinkable liquid crystal monomers with optical activity
(2013-06-25)
Chen Yu-hsien
;
Liu Sheng-fa
;
Li Huai-an
;
Fuh Sin-min
;
Lin Hong-cheu
The present invention relates to photo-crosslinkable liquid crystal monomers with optical activity. The liquid crystal monomers contains one chiral center with an acrylate group or terminal diacrylate groups, and terminal dibenzene rings are introduced in order to extend its hard segment for the purpose of getting a wider liquid crystalline phase. By introducing the liquid crystal monomers, the room temperature nematic liquid crystal or the cholesteric liquid crystal may have a better mutual solubility and a wider, steadier structure of liquid crystal. The liquid crystal monomers have the following formula structure:
Magnetic domain studies of La0.7Sr0.3MnO3 film deposited on SrLaAlO3 (001) substrate
(2013-06-26)
Liu, Chi-Ching
;
Chu, Pei-Yuan
;
Chiang, Yao-Wei
;
Juang, Jenh-Yih
;
Jen, Shien-Uang
Epitaxial 120 nm La0.7Sr0.3MnO3 (LSMO) compressively strained thin films were deposited on single-crystalline SrLaAlO3(0 0 1) (SLAO) substrates by the pulsed laser deposition (PLD) method. From the x-ray diffraction study, we confirmed that the c-axis of the LSMO crystal pointed out of the film plane. Two kinds of magnetic experiments were performed on the film: (i) the in-plane (field H (sic) H-P) and the out-of-plane (field H (sic) H-N) magnetic hysteresis loop measurements and (ii) magnetic force microscopy scans. We have proved from both theory and experiment that the LSMO film should exhibit the weak and tilted perpendicular magnetic anisotropy at room temperature (RT), that is, the easy axis (EA) is tilted relative to the film normal by an angle theta(o) is approxiamtely equals to 37 degrees, when the film is in the demagnetized state. The magnetic domain (MD) structure of the demagnetized LSMO film showed a maze-like pattern. Although from the in-plane hysteresis loop, H-P = 600 Oe seems large enough to saturate the film, the corresponding MD structure was not in a single-domain state. Instead, there were two types of MDs: the canted MD and the saturated MD. The MD patterns of the LSMO film between the demagnetized and the remanent states were different. In addition, there were double-switch phenomena in the out-of-plane hysteresis loop. When vertical bar H-N vertical bar congruent to 140 Oe, a transition of the MD pattern from the maze-like to the closure (or dense-stripe) type occurred.
Distribution of Crystalline Polymer and Fullerene Clusters in Both Horizontal and Vertical Directions of High-Efficiency Bulk Heterojunction Solar Cells
(2013-06-26)
Liu, Chih-Ming
;
Su, Ming-Shin
;
Jiang, Jian-Ming
;
Su, Yu-Wei
;
Su, Chun-Jen
In this study, we used (i) synchrotron grazing-incidence small-/wide-angle X-ray scattering to elucidate the crystallinity of the polymer PBTC12TPD and the sizes of the clusters of the fullerenes PC61BM and ThC61BM and (ii) transmission electron microscopy/electron energy loss spectroscopy to decipher both horizontal and vertical distributions of fullerenes in PBTC12TPD/fullerene films processed with chloroform, chlorobenzene and dichlorobezene. We found that the crystallinity of the polymer and the sizes along with the distributions of the fullerene clusters were critically dependent on the solubility of the polymer in the processing solvent when the solubility of fullerenes is much higher than that of the polymer in the solvent. In particular, with chloroform (CF) as the processing solvent, the polymer and fullerene units in the PBTC12TPD/ThC61BM layer not only give rise to higher crystallinity and a more uniform and finer fullerene cluster dispersion but also formed nanometer scale interpenetrating network structures and presented a gradient in the distribution of the fullerene clusters and polymer, with a higher polymer density near the anode and a higher fullerene density near the cathode. As a result of combined contributions from the enhanced polymer crystallinity, finer and more uniform fullerene dispersion and gradient distributions, both the short current density and the fill factor for the device incorporating the CF-processed active layer increase substantially over that of the device incorporating a dichlorobenzene-processed active layer; the resulting power conversion efficiency of the device incorporating the CF-processed active layer was enhanced by 46% relative to that of the device incorporating a dichlorobenzene-processed active layer.
Enhanced Light Harvesting with a Reflective Luminescent Down-Shifting Layer for Dye-Sensitized Solar Cells
(2013-06-26)
Hosseini, Zahra
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Huang, Wei-Kai
;
Tsai, Cheng-Ming
;
Chen, Teng-Ming
;
Taghavinia, Nima
For a dye-sensitized solar cell with a near-infrared squaraine (SQ1) sensitizer, the photovoltaic performance was enhanced remarkably with a reflective luminescent down-shifting (R-LDS) layer to increase the light-harvesting efficiency at the wavelength region 400-550 nm where the SQ1 dye has weak absorption. Relative enhancements greater than 200% in IPCE near 500 nm and 40-54% in J(SC) were achieved with red phosphor CaAlSiN3:Eu2+ as the LDS material, attaining 5.0 and 4.8% overall efficiencies of power conversion for the R-LDS layer coated on the counter electrode (front illumination) and working electrode (back illumination), respectively.
Simple and Fast Method To Fabricate Single-Nanoparticle-Terminated Atomic Force Microscope Tips
(2013-06-27)
Cheng, Hui-Wen
;
Chang, Yuan-Chih
;
Yuan, Chi-Tsu
;
Tang, Song-Nien
;
Chang, Chia-Seng
This paper introduces a simple, yet controllable scheme to pick up a single 13 nm Au nanoparticle (Au-NP) using the tip of an atomic force microscope (AFM) probe through the application of electrical biases between the tip and the Au-NP. Transmission electron microscope (TEM) images were acquired to verify that a single Au-NP was attached to the AFM probe. We postulate that the mechanism underlying the ability to manipulate individual Au-NPs at the apex of the AFM probe tip is Coulomb interaction induced by tip bias. The AFM tip with the attached Au-NP was then used to study the interaction between a single quantum dot (QD) and the Au-NP. The blinking behavior of single colloidal CdSe/ZnS core/shell QD was significantly suppressed with the approach of the 13 nm Au-NP attached to the AFM tip.