Browsing by Issue Date, starting with "2019-08-07"

Now showing 1 - 20 of 7072

Dependence of the structure and orientation of VSS grown Si nanowires on an epitaxy process
(2019-08-07)
Chiang, Yi-Ting
;
Chou, Yi
;
Huang, Chang-Hsun
;
Lin, Wei-Ting
;
Chou, Yi-Chia
We investigated the vapor-solid-solid growth of Si nanowires from Ni silicides on Si(111), Si(110), and GaN substrates. The morphology and structures of Si on these substrates are distinct, and are dependent on substrate lattices and an epitaxy process during growth. The sidewall facets and epitaxy of silicides and Si were discussed. In addition, Si grown on GaN nanowires was investigated which led to the formation of branched nanowire structures. The Si nanowires/nanodots lie on the surface of GaN nanowires to maintain lower system energy. We manipulated the whole process in a UHV and studied the crystal growth of Si on different lattice substrates. Meanwhile, the process which occurred in a non-UHV led to less regularity on the NiSi2 crystal facets and interface epitaxy between NiSi2 and Si nanowires.
Effects of solvent molecules on hemi-bonded (CH3SH)(2)(+): infrared absorption of [(CH3SH)(2)-X](+) with X = H2O, (CH3)(2)CO, or NH3 and (CH3SH)(n)(+) (n=3-6)
(2019-08-07)
Xie, Min
;
Tsai, Huei-Ru
;
Fujii, Asuka
;
Lee, Yuan-Pern
;
交大名義發表
Three-electron two-center (3e-2c) hemi-bonds play important roles in the oxidation and electron transport of proteins and are implicated to be involved in some neurodegenerative diseases. Our previous investigations on infrared (IR) spectra of (CH3SH)(2)(+) using vacuum-ultraviolet photoionization, infrared dissociation, and time-of-flight detection have shown that (CH3SH)(2)(+) is (3e-2c)-bonded. To investigate the influence of the solvent molecules on the (3e-2c)-bonded (CH3SH)(2)(+) in a supersonic jet, we added H2O or (CH3)(2)CO or NH3 or (CH3SH)(n) (n = 1-4) to (CH3SH)(2)(+) and investigated their IR action spectra. The (3e-2c)-bonded (CH3SH)(2)(+) ion core was maintained when a molecule of H2O or (CH3)(2)CO or CH3SH binds, indicating that the ion core is more stable than the hydrogen bond, whereas the (3e-2c)-bond became broken by a NH3 molecule because the proton transfer led to a more stable hydrogen-bonded structure. The spectral features of the SH-stretching modes of (CH3SH)(n)(+) (n = 3-6) indicate that the (3e-2c)-bonded (CH3SH)(2)(+) ion core is maintained and the first two additional CH3SH are H-bonded to the free SH groups of the ion core. For larger clusters with n = 5 and 6, the additional solvent molecules likely bind to the first solvation shell. These results show also that the (3e-2c)-bonded S therefore S structure is more stable than the S therefore O and S therefore N structures in [(CH3SH)(2)-X](+) with X = H2O or (CH3)(2)CO or CH3SH or NH3.
Microstructures and electrical properties of zirconium doped barium cerate perovskite proton conductors
(2019-08-09)
Jhuang, Jhe-Wei
;
Lee, Kan-Rong
;
Lee, Sheng-Wei
;
Chang, Jeng-Kuei
;
Jang, Shian-Ching
In this work, we vary the Zr to Ce ratio to investigate the microstructures and electrical properties of zirconium doped barium cerates. The solid state reaction is used in synthesizing the BaCe0.8-xZrxY0.2O3 (X = 0.1-0.5). The electron backscatter diffraction (EBSD) is successfully applied to identify the crystal structure of the barium cerates. EBSD results indicate that all samples have the orthorhombic structure. Conductivity measurement results show that for temperatures below 700 degrees C, Zr-doped barium cerates have higher protonic conductivities than oxygen-ion/electron-hole conductivities. The protonic conductivity increases with the Zr content initially, but decreases after the Zr content is higher than 0.3. The protonic conductivity of BCZY0.3 reaches 8.8 mS/cm at 700 degrees C in dry hydrogen atmosphere. Stability test results show that, for stable operation in CO2 atmosphere, the Zr content in barium cerates should be greater than 0.2. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Symmetry of deterministic ratchets
(2019-08-13)
Rozenbaum, V. M.
;
Shapochkina, I., V
;
Teranishi, Y.
;
Trakhtenberg, L., I
;
物理研究所
We consider the overdamped motion of a Brownian particle in an unbiased force field described by a periodic function of coordinate and time. A compact analytical representation has been obtained for the average particle velocity as a series in the inverse friction coefficient, from which follows a simple and clear proof of hidden symmetries of ratchets, reflecting the symmetry of summation indices of the applied force harmonics relative to their numbering from left to right and from right to left. We revealed the conditions under which (i) the ratchet effect is absent; (ii) the ratchet average velocity is an even or odd functional of the applied force, whose dependences on spatial and temporal variables are characterized by periodic functions of the main types of symmetries: shift, symmetric, and antisymmetric, and universal, which combines all three types. These conditions have been specified for forces with those dependences of a multiplicative (or additive-multiplicative) and additive structure describing two main ratchet types, pulsating and forced ratchets. We found the fundamental difference in dependences of the average velocity of pulsating and forced ratchets on parameters of spatial and temporal asymmetry of potential energy of a particle for systems in which the spatial and temporal dependence is described by a sawtooth potential and a deterministic dichotomous process, respectively. In particular, it is shown that a pulsating ratchet with a multiplicative structure of its potential energy cannot move directionally if the energy is of the universal symmetry type in time; this restriction is removed in the inertial regime, but only if the coordinate dependence of the energy does not belong to either symmetric or antisymmetric functions.
Analytics-statistics mixed training and its fitness to semisupervised manufacturing
(2019-08-13)
Parashar, Parag
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Chen, Chun Han
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Akbar, Chandni
;
Fu, Sze Ming
;
Rawat, Tejender S.
While there have been many studies using machine learning (ML) algorithms to predict process outcomes and device performance in semiconductor manufacturing, the extensively developed technology computer-aided design (TCAD) physical models should play a more significant role in conjunction with ML. While TCAD models have been effective in predicting the trends of experiments, a machine learning statistical model is more capable of predicting the anomalous effects that can be dependent on the chambers, machines, fabrication environment, and specific layouts. In this paper, we use an analytics-statistics mixed training (ASMT) approach using TCAD. Under this method, the TCAD models are incorporated into the machine learning training procedure. The mixed dataset with the experimental and TCAD results improved the prediction in terms of accuracy. With the application of ASMT to the BOSCH process, we show that the mean square error (MSE) can be effectively decreased when the analytics-statistics mixed training (ASMT) scheme is used instead of the classic neural network (NN) used in the baseline study. In this method, statistical induction and analytical deduction can be combined to increase the prediction accuracy of future intelligent semiconductor manufacturing.
A Fluorographene-Based Synaptic Transistor
(2019-08-13)
Liu, Bo
;
Hong, Ming-Chun
;
Sahoo, Mamina
;
Ong, Bin Leong
;
Tok, Eng Soon
Exploring brain-inspired synaptic devices has recently become a new focus of research in nanoelectronic communities. In this emerging field, incorporating 2D materials into three-terminal synaptic transistors has brought various advantages. However, achieving a stable and long-term weight-modulation in these synaptic transistors, which are typically based on interface charge storage, is still a challenge due to the nature of their spontaneous relaxation. The application of an atomically thin fluorographene layer into the synaptic junction region suppresses this issue and improves the efficiency, tunability, and symmetry of the synaptic plasticity as well as establishing a stable weight-regulation paradigm. These unique properties can be attributed to the dipolar rotation of C-F in fluorographene. To obtain a better physical understanding, a vacancy-dependent C-F dipolar rotation model is proposed and supported by hysteresis analysis and density functional theory calculations. As proposed and demonstrated, the unique fluorographene-based synaptic transistor may be a promising building block for constructing efficient neuromorphic computing hardware.
Absorption avoided resonance crossing of hybridization of silicon nanoparticles and gold nanoantennas
(2019-08-13)
Yang, Jhen-Hong
;
Yu, Min-Wen
;
Chen, Kuo-Ping
;
光電系統研究所
;
照明與能源光電研究所
The near-field coupling between a high-refractive-index nanoparticle and gold nanoantennas is investigated theoretically. The absorption enhancement and also avoided resonance crossing in the absorption cross section spectra were observed with the hybridization system due to the coupling between the localized surface plasmon resonance of the gold nanoantennas and the magnetic dipole resonance of the silicon nanoparticle. By controlling the nanoparticle size or the separation distance, the near-field coupling can be tuned from the weak to the strong regime.
Characteristics of In0.7Ga0.3As MOS Capacitors Obtained using Hydrochloric Acid Treatment, Ammonium Sulfide Passivation, Methanol Treatment, and Forming Gas Annealing
(2019-08-14)
Chung, Sheng-Ti
;
Huang, Yi-Chin
;
Fu, Yen-Chun
;
Lee, Yao-Jen
;
Chao, Tien-Sheng
This paper proposes a chemical pre-treatment process to reduce sulfate prior to atomic layer deposition of Al2O3 gate dielectrics on n-doped In0.7Ga0.3As layers to form metal oxide semiconductor capacitors (MOSCAPs). Cleaning with methanol was done after hydrogen chloride etching and ammonium sulfide passivation. X-ray photoelectron spectroscopy performed on the sample with methanol cleaning indicated that its native oxide regrowth was effectively prevented on the sulfur-passivated In0.7Ga0.3As surface under air exposure. By analysis using atomic force microscopy of the sample cleaned using methanol, no further increase of surface roughness was observed after 5 months of air exposure. In addition, a mid-gap interface defect density (D-it) of 1.3 x 10(12) cm(-2) eV(-1) was obtained from this sample. After forming gas annealing (FGA), the D-it was improved significantly, to a value below 10(12) cm(-2) eV(-1). The obtained data indicate that the combination of chemical pre-treatment and FGA is advantageous to passivating the trap states on In0.7Ga0.3As MOSCAPs. (C) 2019 The Electrochemical Society.
Forced coplanarity of dithienofluorene-based non-fullerene acceptors to achieve high-efficiency organic solar cells
(2019-08-14)
Cao, Fong-Yi
;
Huang, Po-Kai
;
Su, Yen-Chen
;
Huang, Wen-Chia
;
Chang, Shao-Ling
Ladder-type structures have been the key element for high performance non-fullerene acceptors (NFAs). In this work, two dithieno[3,2-b:6,7-b ']fluorine (DTF)-based nonfullerene acceptors, non-bridged DTFT5-FIC and carbon-bridged DTFT9-FIC, with an identical conjugated backbone were designed and synthesized for investigation of the planarization effect. The chemical rigidification with forced coplanarity indeed plays a pivotal role in determining the molecular properties. Compared to the non-bridged open-chain DTFT5-FIC counterpart, the nonacyclic ladder-type DTFT9-FIC with a fully planarized backbone exhibits higher thermal stability, bathochromic absorption and higher electron mobility. The devices using PBDB-T as the p-type polymer and fully planar DTFT9-FIC as the acceptor showed a high efficiency of 9.58%, which is superior to that of the device using the partially planar DTFT5-FIC material (5.45%). By incorporating PC71BM as the second acceptor to enhance the absorption at shorter wavelengths, optimize the morphology and facilitate electron transport, the ternary-blend device using PBDB-T:DTFT9-FIC:PC71BM achieved the highest PCE of 11.82% with a V-oc of 0.88 V, a higher J(sc) of 20.59 mA cm(-2), and an FF of 65.27%.
Ultrabright Fluorescent Polymer Dots with Thermochromic Characteristics for Full-Color Security Marking
(2019-08-14)
Yang, Jyun-Chi
;
Ho, Yu-Chieh
;
Chan, Yang-Hsiang
;
交大名義發表
;
應用化學系
Innovative and scalable security technologies are in high demand to deter increasing counterfeiting in modern society. Here, we report the first example of thermochromic-fluorescent ink based on semiconducting polymer dots (Pdots) by taking advantage of the unique optical properties of Pdots. We designed and synthesized two types of thermochromic molecules and then incorporated them with multicolor fluorescent Pdots. The resulting Pdots exhibited colorimetric and fluorescent dual-readout abilities in response to different temperatures which greatly increase the security level for anticounterfeiting applications. These multifunctional Pdots can be easily doped into flexible substrates or prepared as inks. These full-color inks can be further loaded into marker pens for handwriting or cartridges for inkjet printing with excellent signal-to-background contrast. Moreover, complex and delicate full-color images can be printed on security documents or currency for practical use. We anticipate that this first example of thermoresponsive dual-readout methodology based on Pdots will have broad use in advanced security marking technologies.
Design, Modeling, and Fabrication of High-Speed VCSEL with Data Rate up to 50 Gb/s
(2019-08-14)
Shen, Chih-Chiang
;
Hsu, Tsung-Chi
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Yeh, Yen-Wei
;
Kang, Chieh-Yu
;
Lu, Yun-Ting
We have studied the characteristics of frequency response at 850-nm GaAs high-speed vertical-cavity surface-emitting lasers (VCSELs) with different kinds of oxide aperture sizes and cavity length using the PICS3D simulation program. Using 5-mu m oxide aperture sizes, the frequency response behavior can be improved from 18.4 GHz and 15.5 GHz to 21.2 GHz and 19 GHz in a maximum of 3 dB at 25 degrees C and 85 degrees C, respectively. Numerical simulation results also suggest that the frequency response performances improved from 21.2 GHz and 19 GHz to 30.5 GHz and 24.5 GHz in a maximum of 3 dB at 25 degrees C and 85 degrees C due to the reduction of cavity length from 3 lambda/2 to lambda/2. Consequently, the high-speed VCSEL devices were fabricated on a modified structure and exhibited 50-Gb/s data rate at 85 degrees C.
Fourier-transform microwave spectroscopy on weakly bound complexes of CH2OO with Ar, CO, and N-2
(2019-08-14)
Nakajima, Masakazu
;
Endo, Yasuki
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應用化學系
;
Department of Applied Chemistry
Pure rotational transitions of weakly bound complexes of the simplest Criegee intermediate CH2OO with Ar, CO, and N-2 are observed by Fourier-transform microwave (FTMW) and FTMW-MW double-resonance spectroscopy. Many of the observed lines show doublet peaks associated with the tunneling splitting between the two equivalent configurations of the complexes. The intermolecular distances of the complexes are derived from the precise rotational constants determined in this study. The separations between two components of the doublet peaks observed for c-type transitions of CH2OO-Ar are satisfactorily demonstrated by a one-dimensional hindered rotor model for the internal rotation of the CH2OO monomer. Published under license by AIP Publishing.
【設計獎道理，創新設計思考】
(國立陽明大學, 2019-08-15)
陽明電子報編輯小組
雙
(國立陽明大學, 2019-08-15)
林心亮
;
陽明電子報編輯小組
【失智防治與銀光經濟產業應用學分班】
(國立陽明大學, 2019-08-15)
陽明電子報編輯小組
陽明GLORIA講座：打造生技獨角獸的專屬平台
(國立陽明大學, 2019-08-15)
陽明電子報編輯小組
7月份的生醫領航方舟企業講座，邀請到以研發小分子新藥亮眼的國鼎生技蘇經天總經理蒞臨分享。蘇總經理以其豐富的經歷與獨到的見解...
AIT司徒文前處長、康照洲院長接任陽明副校長
(國立陽明大學, 2019-08-15)
陽明電子報編輯小組
本校於8月進行行政主管人事調整，美國在台協會（AIT）台北辦事處司徒文（William Stanton）前處長，以及食品藥物管理署康照洲前署...
【108年度會計業務研討會】
(國立陽明大學, 2019-08-15)
陽明電子報編輯小組
Temperature-Dependent Electroabsorption and Electrophotoluminescence and Exciton Binding Energy in MAPbBr(3) Perovskite Quantum Dots
(2019-08-15)
Rana, Shailesh
;
Awasthi, Kamlesh
;
Bhosale, Sumit S.
;
Diau, Eric Wei-Guang
;
Ohta, Nobuhiro
Organic inorganic lead halide perovskite nanocrystals have attracted much attention as promising materials for the development of solid-state light-emitting devices, but the existence of free or bound excitons or the formation of trap states remains under debate. We recorded temperature-dependent electroabsorption (E-A) and electrophotoluminescence (E-PL) spectra, that is, electric field-induced change in absorption and photoluminescence spectra, for methylammonium lead tribromide (MAPbBr(3)) colloidal perovskite nanocrystals, that is, quantum dots (QD), doped in a poly(methyl methacrylate) film in the temperature range of 40-290 K. Based on the results, the binding energy of the exciton (electron hole pair) was estimated. The exciton binding energy of QD of MAPbBr(3) estimated from the absorption and E-A spectra (similar to 17 meV) is nearly the same as that of a MAPbBr(3) polycrystalline thin solid film, while the exciton binding energy estimated from the temperature-dependent PL spectra (similar to 70 meV) is much greater than that estimated from the absorption profile. The frequency dependence of the E-A intensity observed at 40 and 290 K for the modulated applied electric field indicates a slow ion migration in nanocrystals, which follows the modulation of the applied electric field at a frequency less than 500 Hz. The observed E-A spectra were analyzed with an integral method on assuming the Stark effect; the magnitudes of the changes in electric dipole moment and polarizability following photoexcitation were determined at each temperature from 40 to 290 K. E-PL spectra show that the PL of QD of MAPbBr(3) is quenched on the application of an external electric field; the extent of quenching is much greater for trap emission than for exciton emission. Exciton phonon scattering, which is responsible for the line broadening of the PL spectra, is also discussed based on the temperature-dependent PL spectra.
生科院暑期實驗營，開啟生醫學習的大門
(國立陽明大學, 2019-08-15)
陽明電子報編輯小組
「107年暑期生物醫學實驗營」佳評如潮，陽明生命科學院今年暑假繼續辦理「暑期生物醫學實驗營」，共有69位來自全國各地的高中與大...