Browsing by Issue Date, starting with "2018-10-17"

Now showing 1 - 20 of 9693

Environmentally and Mechanically Stable Selenium 1D/2D Hybrid Structures for Broad-Range Photoresponse from Ultraviolet to Infrared Wavelengths
(2018-10-17)
Chen, Yu-Ze
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You, Yen-Ting
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Chen, Pin Jung
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Li, Dapan
;
Su, Teng-Yu
Selenium (Se) is one of the potential candidates as photodetector because of its outstanding properties such as high photoconductivity (similar to 8 x 10(4) S cm(-1)), piezoelectricity, thermoelectricity, and nonlinear optical responses. Solution phase synthesis becomes an efficient way to produce Se, but a contamination issue that could deteriorate the electric characteristic of Se should be taken into account. In this work, a facile, controllable approach of synthesizing Se nanowires (NWs)/films via a plasma-assisted growth process was demonstrated at the low substrate temperature of 100 degrees C. The detailed formation mechanisms of nanowires arrays to thin films at different plasma powers were investigated. Moreover, indium (In) layer was used to enhance the adhesive strength with 50% improvement on a SiO2/Si substrate by mechanical interlocking and surface alloying between Se and In layers, indicating great tolerance for mechanical stress for future wearable devices applications. Furthermore, the direct growth of Se NWs/films on a poly(ethylene terephthalate) substrate was demonstrated, exhibiting a visible to broad infrared detection ranges from 405 to 1555 nm with a high on/off ratio of similar to 700 as well as the fast response time less than 25 ms. In addition, the devices exhibited fascinating stability in the atmosphere over one month.
Large-Scale Transparent Molybdenum Disulfide Plasmonic Photodetector Using Split Bull Eye Structure
(2018-10-18)
Sourav, Adhikary
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Li, Zhiwen
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Huang, Zhonghui
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Botcha, Venkata Divakar
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Hu, Cong
A high performance photodetector array on transparent substrate is highly sought after for enabling next-generation imaging technology at the visible wavelengths. 2D materials such as molybdenum disulfide (MoS2) are attractive for such application owing to its superior optoelectronic properties and transparency when scaled to atomic thinness. Here, direct growth of MoS2 on centimeter-scale transparent Al2O3 substrate is reported using a high yield and scalable chemical vapor deposition approach. This enables a large area photodetector array to be demonstrated, wherein aluminum split bull eye (SBE) plasmonic structure is integrated to achieve further performance boost due to surface plasmon resonance (SPR) effect. For a wavelength of 405 nm, the plasmonic MoS2 detector achieves an ultralow noise equivalent power of approximate to 6.2 x 10-14 W Hz(-1/2) and a high responsivity of 7.26 A W-1 at a small bias of 1.0 V, which is more than 6x larger than the reference detector due to SPR effect. Finite-difference time-domain simulation confirms a higher concentration of optical field distribution at the center of the SBE structure, which is responsible for the enhancement of photocurrent and sensitivity even at low-light condition.
Isomerization of N2O4 in Solid N2H4 and Its Implication for the Explosion of N2O4-N2H4 Solid Mixtures
(2018-10-18)
Raghunath, Putikam
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Lin, M. C.
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交大名義發表
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National Chiao Tung University
The mechanism responsible for the explosion of solid mixtures of nitrogen tetroxide (N2O4) and hydrazine (HZ) or methyl-substituted HZs, detected experimentally by slow warming from 77 to 203-223 K, has been elucidated by quantum chemical calculations using the Vienna ab initio simulation package code. The result of the calculation for the reaction of a N2O4 molecule embedded in the middle of the N2H4 molecular crystal, N2O4@HZ(23), indicates that a loose nonconventional transition state (TS) occurring by stretching the O2N-NO2 bond up to 2.18 A with the concerted rotation of one of the NO2 groups producing the reactive ONONO2 isomer (ONONO2@HZ(23)) has a low 13.1 kcal/mol barrier at TS1; the process is exothermic by 45 kcal/mol, reflecting the much stronger ONONO2 binding with N2H4. A further simultaneous reaction of ONONO2 with 2N(2)H(4) in the same unit cell occurs with a small 1.4 kcal/mol barrier producing NO3- + NH2N(H)NO + N2H5+ with an overall exothermicity of 70.2 kcal/mol. The mechanism for this last-step reaction is distinctly different from that in the gas phase taking place via a five-centered concert mechanism giving N2H3NO and HNO3, which can further produce N2H5+NO3- by the rapid acid-base neutralization process. On the basis of the predicted structure, energy, and vibrational frequencies at TS1, we estimated the rate constant at 218 K for the N2O4-ONONO2 isomerization reaction in solid N2H4 to be 1.35 s(-1), giving the half-life of N2O4 @HZ 23 to be as short as 0.5 s. This result can explain why the slow warming of the solid mixtures of N2O4 and N2H4 from 77 K exploded reproducibly at 218 K.
Performance analysis of free space optical communication traffic integrated with passive optical network
(2018-10-18)
Yeh, C. H.
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Chow, C. W.
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Gu, C. S.
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Guo, B. S.
;
Cheng, Y. J.
In this Letter, a hybrid 10 Gbit/s on-off keying free space optics and passive optical network (FSO-PON) system is proposed and demonstrated. The experimental received sensitivities are -18 and -20 dBm at the back to back (BtB) and after 25 km fibre transmission, respectively, with 5 m free space traffic link. In the proposed analysis, FSO-PON system can support 32 and 16; and 8 and 4 remote optical wireless units for free space communication at BtB and after 25 km fibre link, respectively, when the free space transmission lengths are 150 and 300 m.
Negative-Differential-Resistance Devices Achieved by Band-Structure Engineering in Silicene under Periodic Potentials
(2018-10-18)
Chen, Chang-Hung
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Li, Wen-Wu
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Chang, Yuan-Ming
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Lin, Che-Yi
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Yang, Shih-Hsien
An important development in modern electronics is the realization of band-structure engineering for the design of novel materials and devices. One possible way to realize band-structure engineering is by addition of periodic potentials to two-dimensional (2D) materials, such as graphene, to form a superstructure, known as a "superlattice.' Unlike the band gap of graphene, the band gap of silicene can be tuned by an out-of-plane electric field owing to its unusual buckled structure. In this work, we use the designable band gap of silicene and the band structure of superlattices, together with the spin and valley degrees of freedom, to propose a design principle for optimizing the performance of spin-and valley-dependent negative-differential-resistance (NDR) devices using silicene superlattices. On the basis of the effective Hamiltonian formalism, we predict that the peak-to-valley current ratio could be larger than most recently reported results achieved by 2D materials, suggesting that the silicene superlattice is a good candidate for realizing NDR devices. The design principle proposed in this work could also be extended to other layered materials with tunable band gaps. This could pave the way for advanced material and device designs based on band-gap engineering of 2D materials.
Switching Failure Mechanism in Zinc Peroxide-Based Programmable Metallization Cell
(2018-10-19)
Simanjuntak, Firman Mangasa
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Chandrasekaran, Sridhar
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Lin, Chun-Chieh
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Tseng, Tseung-Yuen
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電子工程學系及電子研究所
The impact of peroxide surface treatment on the resistive switching characteristics of zinc peroxide (ZnO2)-based programmable metallization cell (PMC) devices is investigated. The peroxide treatment results in a ZnO hexagonal to ZnO2 cubic phase transformation; however, an excessive treatment results in crystalline decomposition. The chemically synthesized ZnO2 promotes the occurrence of switching behavior in Cu/ZnO2/ZnO/ITO with much lower operation current as compared to the Cu/ZnO/ITO (control device). However, the switching stability degrades as performing the peroxide treatment for a longer time. We suggest that the microstructure of the ZnO2 is responsible for this degradation behavior and fine tuning on ZnO2 properties, which is necessary to achieve proper switching characteristics in ZnO2-based PMC devices.
交大e-News第265期-悼永遠的交大人張俊彥校長
(2018-10-19)
國立交通大學秘書室
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Secretariat
Optimal electromechanical control of the excitonic fine structures of droplet epitaxial quantum dots
(2018-10-19)
Cheng, Shun-Jen
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Yang, Yi
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Wu, Yu-Nien
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Liao, Yu-Huai
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Peng, Guan-Hao
The intrinsic fine structure splittings (FSSs) of the exciton states of semiconductor quantum dots (QDs) are known to be the major obstacle for realizing the QD-based entangled photon pair emitters. In this paper, we present a theoretical and computational investigation of the excitonic fine structures of droplet-epitaxial (DE) GaAs/AlGaAs QDs under the electromechanical control of micromachined piezoelectric actuators. From the group theory analysis with numerical confirmation based on the developed exciton theory, we reveal the general principle for the optimal design of micromachined actuators whose application onto an elongated QD can certainly suppress its FSS. We show that the use of two independent tuning stresses is sufficient to achieve the FSS elimination but is not always necessary as widely deemed. The use of a single tuning stress to eliminate the FSS of an elongated QD is possible as long as the crystal structure of the actuator material is in coincidence with that of the QD. As a feasible example, we show that a single symmetric biaxial stress naturally generated from the (001) [Pb(Mg1/3Nb2/3)O-3](0.)(72)-[PbTiO3](0.)(28) (PMN-PT) actuator can be used as a single tuning knob to make the full FSSelimination for elongated DE GaAs QDs.
在奶媽家，長大前的每一天
(2018-10-21)
陳子與
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Department of Communication and Technology
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傳播與科技學系
爸爸媽媽去上班，小孩就到奶媽家玩。看阿亮、米寶、阿綦，一整天怎麼玩！
Challenge Women　女性運動派對
(2018-10-21)
廖庭歡
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Department of Communication and Technology
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傳播與科技學系
Challenge Women是一場從國外引進的女性運動派對，主旨為透過運動展現女性的自信與美麗，不管你是青春年華的18歲，還是一個孩子的媽，永遠都可以是那個最自信的女孩。
時空隧道　回到1920大稻埕
(2018-10-21)
洪蜜禪
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Department of Communication and Technology
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傳播與科技學系
大稻埕藝術節活動「時空劇場─1920變裝遊行」在10月14日舉行，以「狂騷」為主題，參與民眾穿上繽紛古裝，共襄盛舉。
招呼拉客　漁港的美食競爭　
(2018-10-21)
程安瑜
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Department of Communication and Technology
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傳播與科技學系
在人潮洶湧的觀光漁港當中，一個嬌小的身影穿梭，只為在生意競爭激烈下，幫助店家多招呼一位客人。
台灣網劇新型態　BL劇崛起
(2018-10-21)
陳盈璇
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Department of Communication and Technology
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傳播與科技學系
近年來台灣許多公司開始陸續製播同性題材的自製劇，《HIStory》系列的總體點擊率更是突破千萬。
我的夢想是一架墜落的樂章
(2018-10-21)
呂奕廷
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Department of Communication and Technology
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傳播與科技學系
夢想是童年射出的紙飛機，還以為能永遠自在地翱翔，卻在途中墜落，落入深不見底的黑洞。
竹東市場　一日之計在於晨
(2018-10-21)
顏筱娟
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Department of Communication and Technology
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傳播與科技學系
多達700多個攤位的竹東市場，走過一甲子的歲月，每一個人物、行為、精神，編織起來都是一篇篇獨特的故事。
脊髓裡的小裝置，讓癱瘓者重生
(2018-10-21)
黃俊軒
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Department of Communication and Technology
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傳播與科技學系
利用神經刺激器，讓先前被判斷失去站起來權利的病患，獲得再次行走的機會。
宇宙大爆炸　藝術書市集草率祭
(2018-10-21)
殷顗霖
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Department of Communication and Technology
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傳播與科技學系
至今已邁入第三屆的草率祭，再度於松山文創園區舉辦。超過一百組來自世界各國的獨立出版單位參展，華麗地滿足你的藝術夢。
總編輯的話
(2018-10-21)
唐承安
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Department of Communication and Technology
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傳播與科技學系
本期為喀報第298期，共計24篇稿件。本期頭題為梁書瑜的柿代相傳的好滋味　新埔柿餅。此外，林芷懷所撰寫的淺灘之下一個巨星的誕生也是極為出色。
有錢也難買到　限量令人瘋狂
(2018-10-21)
李沛榆
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Department of Communication and Technology
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傳播與科技學系
當商品有了「限量」加持，身價水漲船高但卻受人追捧，形成了另類的文化。
歡迎來到我的葬禮Party
(2018-10-21)
何浚捷
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Department of Communication and Technology
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傳播與科技學系
我的葬禮我做主！這一次，我要用葬禮顛覆你們對於葬禮的刻板印象，因為我的葬禮，沒有眼淚。