Browsing by Issue Date, starting with "2006-10-14"

Now showing 1 - 20 of 62594

Photodissociation dynamics of fluorobenzene (C6H5F) at 157 and 193 nm: Branching ratios and distributions of kinetic energy
(2006-10-14)
Lee, Shih-Huang
;
Wu, Chia-Yan
;
Yang, Sheng-Kai
;
Lee, Yuan-Pern
;
應用化學系
Following photodissociation of fluorobenzene (C6H5F) at 193 and 157 nm, we detected the products with fragmentation-translational spectroscopy by utilizing a tunable vacuum ultraviolet beam from a synchrotron for ionization. Between two primary dissociation channels observed upon irradiation at 193 (157) nm, the HF-elimination channel C6H5F -> HF+C6H4 dominates, with a branching ratio of 0.94 +/- 0.02 (0.61 +/- 0.05) and an average release of kinetic energy of 103 (108) kJ mol(-1); the H-elimination channel C6H5F -> H+C6H4F has a branching ratio of 0.06 +/- 0.02 (0.39 +/- 0.05) and an average release of kinetic energy of 18.6 (26.8) kJ mol(-1). Photofragments H, HF, C6H4, and C6H4F produced via the one-photon process have nearly isotropic angular distributions. Both the HF-elimination and the H-elimination channels likely proceed via the ground-state electronic surface following internal conversion of C6H5F; these channels exhibit small fractions of kinetic energy release from the available energy, indicating that the molecular fragments are highly internally excited. We also determined the ionization energy of C6H4F to be 8.6 +/- 0.2 eV. (c) 2006 American Institute of Physics.
Dual-band multiplexer/demultiplexer with photonic-crystal-waveguide couplers for bidirectional communications
(2006-10-15)
Chien, Forest Shih-Sen
;
Cheng, Sue- Cheng
;
Hsu, Yu-Ju
;
Hsieh, Wen-Feng
;
光電工程學系
An ultrashort photonic-crystal-waveguide (PCW) coupler is numerically designed for dual-band multiplexing/demultiplexing (Muxing/Demuxing). The PCW coupler consists of two line defects of reduced rods in a triangular lattice and Muxing/Demuxing is implemented by the distinction between coupling and decoupling of PCWs. Since waves tend to highly localize within the reduced rods, the backward coupling is suppressed and the efficiency of Muxing/Demuxing is enhanced as compared with the void-rod PCWs. The coupler is utilized to build a bidirectional system for dual-band duplex communications. (c) 2006 Elsevier B.V. All rights reserved.
Effect of uniaxial strain on anisotropic diffusion in silicon
(2006-10-16)
Chen, Ming-Jer
;
Sheu, Yi-Ming
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A physical model is directly extended from the thermodynamic framework to deal with anisotropic diffusion in uniaxially stressed silicon. With the anisotropy of the uniaxial strain induced activation energy as input, two fundamental material parameters, the activation volume and the migration strain anisotropy, can be quantitatively determined. When applied to boron, a process- device coupled simulation is performed on a p-type metal-oxide-semiconductor field-effect transistor undergoing uniaxial stress in a manufacturing process. The resulting material parameters have been found to be in satisfactory agreement with values presented in the literature. (c) 2006 American Institute of Physics.
Convergence of phase noise in DPSK transmission systems by novel phase noise averagers
(2006-10-16)
Wei, Chia Chien
;
Chen, Jason (Jyehong)
;
光電工程學系
;
Department of Photonics
This investigation proposes a novel all-optical phase noise averager to reduce residual phase noise in the differential phase-shift keying (DPSK) transmission system with phase-preserving amplitude regenerators. The proposed phase noise averager is based on a phase-sensitive amplifier but does not require an extra phase-locking optical pump beam. It can increase the correlation between the phase noises of neighboring bits and greatly reduce the differential phase noise in the transmission system. Independently of the cascaded spans, analytical analysis demonstrates that, in the DPSK system with repeated averagers, the total differential phase noise will be less than that before the first averager. Theoretical analysis and numerical simulation are carried out and confirm the significant improvement of DPSK signals using the proposed novel phase noise averagers. (c) 2006 Optical Society of America
具銅金屬化之複合物半導體元件
(2006-10-16)
張翼
;
張尚文
;
李承士
本發明係為一具銅金屬化之複合物半導體元件，結構為異質接面雙載子電晶體(HBT)結構，當基板為砷化鎵基板時，其歐姆接觸層之材料為鈀／鍺／氮化鎢／銅或鉑／鈦／鉑／銅，而金屬連接線為鈦／鉑／銅；若基板為磷化銦基板時，歐姆接觸層之材料為鈦／鉑／銅或鉑／鈦／鉑／銅，金屬連接線為鈦／鉑／銅，藉由具有較佳散熱特性之銅取代金，可增加其散熱效果，進而增加元件的可靠度。
Luminescence properties of wurtzite AlN nanotips
(2006-10-16)
Shi, Shih-Chen
;
Chen, Chia Fu
;
Chattopadhyay, Surojit
;
Chen, Kuei-Hsien
;
Ke, Bo-Wen
The optical properties of aluminum nitride nanotips (AlNNTs) synthesized via vapor transport and condensation process have been studied by cathodoluminescence, photoluminescence (PL), thermoluminescence (TL), and UV absorption measurements. Two defect related transitions around 2.1 and 3.4 eV and an excitonic feature at 6.2 eV were identified. Compared to the AlN macropowders, the AlNNTs showed a blueshift (+0.2 eV) of the similar to 3.2 eV peak. Analysis of both PL and TL excitation measurements indicated the existence of subband gap multiple energy levels in AlNNTs. A significant TL intensity even at 145 degrees C suggests possible ultraviolet detector and dosimetric applications of these AlNNTs. (c) 2006 American Institute of Physics.
語音定位系統
(2006-10-16)
胡竹生
;
劉維瀚
;
鄭价呈
本發明係為一語音定位方法與系統，將聲音訊號藉由麥克風陣列接收並傳送至語音偵測系統，以決定系統之運作狀態流程，再將聲波訊號傳送至環境參數訓練子系統藉由加成性原理模擬產生訓練訊號，並將該訓練訊號經由特徵之抽取及描述此特徵之分佈狀況以產生一統計參數，最後將麥克風陣列所擷取之聲音訊號及統計參數驅動語音位置偵測子系統以偵測語者位置。
無線區域網路支援服務品質之排程方法
(2006-10-16)
黃經堯
;
范裕隆
一種無線區域網路(WLAN)中站台之輪詢方法，包含下列步驟：取得相關於該等站台之服務品質(QoS)資訊；指定兩個計時器於需要該QoS保證之各該WLAN服務，一用於向上連結傳輸及另一用於向下連結傳輸；當該等計時器之具有最小值的計時器Tm之值低於一臨限值Tthr時，則起始一控制之存取週期(CAP)；與具有最小值計時器Tm之站台交換訊息(依據需要來輪詢，或向下連結與輪詢)；在傳送一輪詢之訊息之後，更新該具有最小值之計時器Tm；其中，若該Tm之值大於該臨限值Tthr時，退出該CAP並允許其它站台競爭資源。
L-band Erbium-doped fiber laser with coupling-ratio controlled wavelength tunability
(2006-10-16)
Lin, Gong-Ru
;
Chang, Jun-Yuan
;
Liao, Yu-Sheng
;
Lu, Hai-Han
;
光電工程學系
By controlling the output coupling ratio, we demonstrate a novel wavelength-tunable L-band Erbium-doped fiber laser (EDFL) with a maximum tuning range up to 58 nm ( from 1567 to 1625 nm) by controlling its output coupling ratio between 1% and 99%. The L-band EDFL is configured by using a bi-directionally dual-wavelength pumped EDFA in close-loop with an output coupler of tunable coupling ratio and an air-gap inserted FC/PC connector pair. Such an EDFL exhibits a quantum efficiency of 42% and an ultra-high power conversion efficiency of 37% under optimized pumping scheme, providing the small-signal gain and output power of similar to 34 dB and 91 mW, respectively. Low variation of < 1.2 dB on channel power, power fluctuation of 0.04% and a narrow linewidth of 0.03 nm are obtained. (c) 2006 Optical Society of America
低音補強模組之微型喇叭
(2006-10-16)
白明憲
;
廖哲緯
本發明係一種低音補強模組之微型喇叭，適用於手提式裝置，如手機、掌上型遊戲機、PDA者，其係由音箱、凹槽及管路所組成。在音箱的側緣設二開口分別與連接凹槽及管路連接。凹槽內具有單體喇叭，管路係低音反射管。管路之音量與管路的面積及長度有關，與形狀無關，因此本發明可依據不同之形狀需求(如不同之手機造型需求)設計出不同之低音反射管以符合所需，藉由低音反射管增強微型喇叭的低音響應頻率，並不會因為手機容積變小，使低音響應頻率之效果變差。
Spatial and energetic distribution of border traps in the dual-layer HfO2/SiO2 high-k gate stack by low-frequency capacitance-voltage measurement
(2006-10-16)
Wu, Wei-Hao
;
Tsui, Bing-Yue
;
Chen, Mao-Chieh
;
Hou, Yong-Tian
;
Jin, Yin
Threshold voltage instability measured by the pulse current-voltage technique has been recognized as the transient charging and discharging of the preexisting bulk traps in Hf-based high-k gate dielectrics, and these high-k traps or called border traps can instantly exchange charge carriers with the underlying Si substrate by tunneling through the thin interfacial oxide. Based on an elastic tunneling model through trapezoidal potential barriers, the spatial and energetic distribution of border traps in the HfO2/SiO2 high-k gate stack can be profiled as a smoothed, three-dimensional mesh by measuring the low-frequency capacitance-voltage characteristics of high-k metal-oxide-semiconductor capacitors with n-type Si substrate.
結合格狀調變碼（TCM）與低複雜度對稱檢查（LDPC）碼之傳輸方法及其架構
(2006-10-16)
林建青
;
張錫嘉
;
李鎮宜
本發明係揭露一種結合格狀調變碼(TCM)與低複雜度對稱檢查(LDPC)碼之傳輸方法及其架構，其係藉由兩種編碼方式的結合，將錯誤更正能力較強的LDPC碼搭配TCM技術，以提升傳輸品質並定義出不同的傳輸速率TCM。另外，TCM可以利用較少的狀態數達到比習知展頻(spreading)更好的效能，降低在高速傳輸的應用領域的硬體複雜度。
應用於積體電路之微型電感
(2006-10-16)
郭建男
;
馬健嘉
一種應用於積體電路之微型電感，包括具有共平面帶線之一半導體基板以及多數個MIM電容，其中這些MIM電容相互平行連接於共平面帶線之傳輸線問，且連接這些MIM電容之共平面帶線更包括交叉型平面帶線結構或平移型平面帶線結構。本發明使用加入MIM電容以及對折傳輸線的方式，減小電感所佔用之面積，並減輕電感受基材損耗影響的值品質因子之問題。
Extraction of nitride trap density from stress induced leakage current in silicon-oxide-nitride-oxide-silicon flash memory
(2006-10-16)
Gu, Shaw-Hung
;
Wang, Tahui
;
Lu, Wen-Pin
;
Ku, Yen-Hui Joseph
;
Lu, Chih-Yuan
The authors propose a technique to extract a silicon nitride trap density from stress induced leakage current in a polycrystalline silicon-oxide-nitride-oxide-silicon flash memory cell. An analytical model based on the Frenkel-Poole emission is developed to correlate a nitride trap density with stress induced leakage current. The extracted nitride trap density is 7.0x10(12) cm(-2) eV(-1). They find that nitride trapped charges have a rather uniform distribution in an energy range of measurement (similar to 0.2 eV). (c) 2006 American Institute of Physics.
Improved memory window for Ge nanocrystals embedded in SiON layer
(2006-10-16)
Tu, Chun-Hao
;
Chang, Ting-Chang
;
Liu, Po-Tsun
;
Liu, Hsin-Chou
;
Sze, Simon M.
The formation of germanium (Ge) nanocrystals embedded in silicon oxygen nitride (SiON) is proposed for charge storage elements in this work. The Ge nanocrystals can be nucleated after the oxidation process of silicon germanium nitride (SiGeN) layer at high temperatures. Compared to the control samples of Ge nanocrystals/SiO2/Si structure and SiON/Si stack memory, the proposed Ge nanocrystals/SiON/Si memory obtained superior memory window, even larger than the typical sum of both. It is considered that the extra interface trap states between Ge and SiON film were generated as Ge nanocrystals were embedded in SiON layer. (c) 2006 American Institute of Physics.
Synthesis and characterization of kinked and hyperbranched carbazole/fluorene-based copolymers
(2006-10-17)
Wu, Chung-Wen
;
Lin, Hong-Cheu
;
材料科學與工程學系
;
Department of Materials Science and Engineering
To decrease the aggregation phenomena and improve the luminescent properties of polyfluorenes (PFs), a series of novel kinked and hyperbranched carbazole units were copolymerized by the Suzuki coupling polycondensation reaction to introduce disorder packing into the copolymer backbones. The thermal, photophysical, electrochemical, and electroluminescent properties of the copolymers were investigated. All of these polymers possess excellent thermal stability with onset decomposition temperatures at 407-466 degrees C and glass transition temperatures at 109-140 degrees C. Photoluminescent (PL) studies showed that these polymers were promising blue light-emitting materials, which exhibited high quantum efficiencies in solution and solid states. Long wavelength emissions at 500-600 nm, which were typical for PFs due to their self-aggregation in the solid state, were suppressed in these polymers. Annealing studies under air showed both improved thermal and photoluminescence stability of the polymers. It was proven that HOMO energy levels of the copolymers can be enlarged by increasing the carbazole content in the electrochemical measurements; hence, the hole injection was greatly enhanced. Pure-blue electroluminescence (EL) spectra with narrow fwhm (full width at the half-maximum) values (39-42 nm) and negligible low-energy excimer emission bands were successfully achieved, indicating that these copolymers could be good candidates for blue light-emitting materials.
Metal oxide-assisted laser desorption/ionization mass spectrometry
(2006-10-17)
Chen
;
Yu-Chie
;
Chen
;
Cheng-Tai
;
Lin
The invention provides a simple, rapid and cost-effective metal oxide-assisted laser desorption/ionization mass spectrometry (MOALDI MS) without the addition of light-absorbing organic-matrix, comprising the use of (a) an inorganic metal oxide with light absorbing capability as an assisting material to render desorption/ionization of samples in laser desorption/ionization mass spectrometry and (b) a citric acid buffer as the proton source for enhancing the ionization efficiency for analytes. Metal oxide assisting materials is not only restricted to the uses of films. Metal oxide nanoparticles are also suitable to be used as the assisting materials. Low matrix background, stable surface feature, homogeneous sample deposition, and wide detectable mass range are the merits of MOALDI MS.
陶藝展陶畫詩三合一
(2006-10-17)
黃俊銘
Magnetoresistance and percolation in Au-p-(PrBa2Cu3O7)(1-p) composites
(2006-10-18)
Le Touze, C.
;
Lin, J. J.
;
電子物理學系
;
物理研究所
;
Department of Electrophysics
We examine the transverse magnetoresistance of three-dimensional bicomponent composites Au-p-(PrBa2Cu3O7)(1-p). This property, seldom measured on percolation systems, has been measured below 5 K and up to 1.5 T. Contrarily to well known transport properties, the magnetoresistance of these compounds exhibits a metal volume fraction's threshold pc linked to the onset of disorder rather than to percolation.
Chirped modulation of molecular vibration in quinoidal thiophene after sub-5 fs excitation
(2006-10-19)
Wang, Zhuan
;
Otsubo, Tetsuo
;
Kobayashi, Takayoshi
;
電子物理學系
;
Department of Electrophysics
Fourier transformation of the real-time trace of sub-5 fs pump-induced molecular vibration in quinoidal thiophene in solution revealed coupled modes to the electronic excitation at 206, 447, and 1466 cm(-1). Spectrogram analysis of 1466 cm(-1) (C=C stretching) mode showed that the amplitude and frequency of the mode are modulated with another low-frequency mode at about 220 cm(-1), which is down chirped being induced by the coupling with modes of even lower frequency, resulting in the irreversible relaxation due to high mode density in the low-frequency range. This Letter thus reports on observation of the modulation of vibrational frequency with a chirped frequency. (c) 2006 Elsevier B.V. All rights reserved.