• Title/Summary/Keyword: barrier performance

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Solution-Processed Quantum-Dots Light-Emitting Diodes with PVK/PANI:PSS/PEDOT:PSS Hole Transport Layers

  • Park, Young Ran;Shin, Koo;Hong, Young Joon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.146-146
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    • 2015
  • We report the enhanced performance of poly(N-vinylcarbozole) (PVK)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based quantum-dot light-emitting diodes by inserting the polyaniline:poly (p-styrenesulfonic acid) (PANI:PSS) interlayer. The QD-LED with PANI:PSS interlayer exhibited a higher luminance and luminous current efficiency than that without PANI:PSS. Ultraviolet photoelectron spectroscopy results exhibited different electronic energy alignments of QD-LEDs with/without the PANI:PSS interlayer. By inserting the PANI:PSS interlayer, the hole-injection barrier at the QD layer/PVK interface was reduced from 1.45 to 1.23 eV via the energy level down-shift of the PVK layer. The reduced barrier height alleviated the interface carrier charging responsible for the deterioration of the current and luminance efficiency. This suggests that the insertion of PANI:PSS interlayer in QD-LEDs contributed to (i) increase the p-type conductivity and (ii) reduce the hole barrier height of QDs/PVK, which are critical factors leading to improve the efficiency of QD-LEDs.

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The Microcosm study for evaluating biobarrier application on sequential degradation of TCE products by Gasoline-Degradaing Mixed Culture

  • Lee, Jae-Sun;Lee, Si-Jin;Lee, Young-Kee;Chang, Soon-Woong
    • 한국생물공학회:학술대회논문집
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    • 2003.10a
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    • pp.440-444
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    • 2003
  • A new approach for ground water treatment combines a permeable Fe(0) barrier to breakdown higher chlorinated solvents like PCE and TCE with a down gradient aerobic biological treatment system to biotransform less chlorinated solvents, such as DCE and vinyl chloride (VC). The expected bacterial performance down gradient of an Fe(0) barrier was evaluated through laboratory batch experiments with a toluene-degrading mixed culture that cometabolically transforms cis-1,2-DCE and VC. The amount of cis-1,2-DCE (initially at 2,000 ppb) and VC (initially at 2,000 ppb) transformed was controlled by the initial toluene(20,000 ppb) concentration. VC was removed much more effectively than Cis-1,2-DCE, and a higher toluene concentration in comparison to the co-substrate concentrations was needed for complete co-substrate removal. Overall, the coupling of an Fe(0) barrier and subsequent biodegradation appears feasible for remediation of complex mixtures of chlorinated solvents and petroleum hydrocarbons in groundwater.

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Improvement in Catalytic NOx Reduction by Using Dielectric Barrier Discharge (유전체장벽방전을 이용한 촉매공정의 질소산화물 저감성능 향상)

  • Mok, Young Sun;Nam, Chang-Mo
    • Journal of the Korean Society of Industry Convergence
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    • v.9 no.1
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    • pp.13-19
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    • 2006
  • The ozone produced by a dielectric barrier discharge device was injected into the exhaust gas to oxidize a part of NO to $NO_2$, and then the exhaust gas containing the mixture of NO and $NO_2$ was further treated in a catalytic reactor where both NO and $NO_2$ were reduced to $N_2$ in the presence of ammonia as the reducing agent. The $NO_2$ content in the mixture of NO and $NO_2$ was changed by the amount of ozone added to the exhaust gas. The experiments were primarily concerned with the effect of reaction temperature on the catalytic $NO_x$ reduction at various $NO_2$ contents. The increase in the $NO_2$ content by the ozone injection remarkably improved the performance of the catalytic $NO_x$ reduction, especially at low temperatures.

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Schottky Barrier MOSFETs with High Current Drivability for Nano-regime Applications

  • Jang, Moon-Gyu;Kim, Yark-Yeon;Jun, Myung-Sim;Choi, Chel-Jong;Kim, Tae-Youb;Park, Byoung-Chul;Lee, Seong-Jae
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.6 no.1
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    • pp.10-15
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    • 2006
  • Various sizes of erbium/platinum silicided n/p-type Schottky barrier metal-oxide-semiconductor field effect transistors (SB-MOSFETs) are manufactured from $20{\mu}m$ to 10nm. The manufactured SB-MOSFETs show excellent DIBL and subthreshold swing characteristics due to the existence of Schottky barrier between source and channel. It is found that the minimization of trap density between silicide and silicon interface and the reduction of the underlap resistance are the key factors for the improvement of short channel characteristics. The manufactured 10 nm n-type SBMOSFET showed $550{\mu}A/um$ saturation current at $V_{GS}-V_T$ = $V_{DS}$ = 2V condition ($T_{ox}$ = 5nm) with excellent short channel characteristics, which is the highest current level compared with reported data.

Development of a Three-Dimensional Barrier Embedded Kenics Micromixer by Means of a Micro-Stereolithography Technology (마이크로 광 조형기술을 이용한 3차원의 배리어가 포함된 케닉스 마이크로 믹서의 개발)

  • Lee In Hwan;Kwon Tai Hun;Cho Dong-Woo;Kim Dong Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.6 s.237
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    • pp.904-912
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    • 2005
  • The flow in a microchannel is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved. In this regard, we developed a novel chaotic micromixer, named Barrier Embedded Kenics Micromixer (BEKM). In the BEKM, the higher level of chaotic mixing can be achieved by combining two general chaotic mixing mechanisms: (i) splitting/reorientation by helical elements inside the microchannel and (ii) stretching/folding via periodically located barriers on the channel wall. The fully three-dimensional geometry of BEKM was realized by a micro-stereolithography technology, in this study, along with a Kenics micromixer and a circular T-pipe. Mixing performances of three micromixers were experimentally characterized in terms of an average mixing color intensity of phenolphthalein. Experimental results show that BEKM has better mixing performance than other two micromixers. Chaotic mixing mechanism, proposed in this study, could be integrated as a mixing component with Micro-Total-Analysis-System, Lab-on-a-chip and so on.

Pulse Density Modulated ZVS High Frequency Inverter with Reverse Blocking Single Switch for Dielectric Barrier Discharge Lamp Dimming

  • Sugimura Hisayuki;Yasui Kenji;Omori Hideki;Lee Hyun-Woo;Nakaoka Mutsuo
    • Proceedings of the KIPE Conference
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    • 2006.06a
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    • pp.206-209
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    • 2006
  • At present, the cold cathode fluorescent lamp (CCFL) using mercury lamp has been generally used far liquid crystal backlight source of personal computer and car navigation and so on. This kind of lamp is more excellent on luminance performance and cost. However, the requirements of liquid crystal backlight due to a light source without mercury have been strongly increased from a viewpoint of the actual influence on environmental preservation and environmental recycling. As fluorescent lamp without mercury, Dielectric Barrier Discharge based rare gas fluorescent lamp (DBD-FL) using xenon (Xe) gas has been studied so far. This DBD lamp has no influence on the human body and environmental recycle. Its operating life is long because electrode is out. In this paper, the simulation and experimental results of soft switching high frequency inverter with reverse blocking single switch as a high frequency power supply circuit for DBD-FL using Xe gas are comparatively evaluated and discussed from a practical point of view.

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Novel properties of erbium-silicided n-type Schottky barrier metal-oxide-semiconductor field-effect-transistors

  • Jang, Moon-Gyu;Kim, Yark-Yeon;Shin, Jae-Heon;Lee, Seong-Jae;Park, Kyoung-Wan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.4 no.2
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    • pp.94-99
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    • 2004
  • silicided 50-nm-gate-length n-type Schottky barrier metal-oxide-semiconductor field-effect-transistors (SB-MOSFETs) with 5 nm gate oxide thickness are manufactured. The saturation current is $120{\mu}A/{\mu}m$ and on/off-current ratio is higher than $10^5$ with low leakage current less than $10{\mu}A/{\mu}m$. Novel phenomena of this device are discussed. The increase of tunneling current with the increase of drain voltage is explained using drain induced Schottky barrier thickness thinning effect. The abnormal increase of drain current with the decrease of gate voltage is explained by hole carrier injection from drain into channel. The mechanism of threshold voltage increase in SB-MOSFETs is discussed. Based on the extracted model parameters, the performance of 10-nm-gate-length SB-MOSFETs is predicted. The results show that the subthreshold swing value can be lower than 60 mV/decade.

Study of Nonvolatile Memory Device with SiO2/Si3N4 Stacked Tunneling Oxide (SiO2/Si3N4 터널 절연악의 적층구조에 따른 비휘발성 메모리 소자의 특성 고찰)

  • Cho, Won-Ju
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.1
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    • pp.17-21
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    • 2009
  • The electrical characteristics of band-gap engineered tunneling barriers consisting of thin $SiO_2$ and $Si_3N_4$ dielectric layers were investigated for nonvolatile memory device applications. The band structure of band-gap engineered tunneling barriers was studied and the effectiveness of these tunneling barriers was compared with the conventional tunneling $SiO_2$ barrier. The band-gap engineered tunneling barriers composed of thin $SiO_2$ and $Si_3N_4$ layers showed a lower operation voltage, faster speed and longer retention time than the conventional $SiO_2$ tunnel barrier. The thickness of each $SiO_2$ and $Si_3N_4$ layer was optimized to improve the performance of non-volatile memory.

Lifetime Performance of EB-PVD Thermal Barrier Coatings with Coating Thickness in Cyclic Thermal Exposure

  • Lu, Zhe;Lee, Seoung Soo;Lee, Je-Hyun;Jung, Yeon-Gil
    • Korean Journal of Materials Research
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    • v.25 no.10
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    • pp.571-576
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    • 2015
  • The effects of coating thickness on the delamination and fracture behavior of thermal barrier coating (TBC) systems were investigated with cyclic flame thermal fatigue (FTF) and thermal shock (TS) tests. The top and bond coats of the TBCs were prepared by electron beam-physical vapor deposition and low pressure plasma spray methods, respectively, with a thickness ratio of 2:1 in the top and bond coats. The thicknesses of the top coat were 200 and $500{\mu}m$, and those of the bond coat were 100 and $250{\mu}m$. FTF tests were performed until 1140 cycles at a surface temperature of $1100^{\circ}C$ for a dwell time of 5 min. TS tests were also done until more than 50 % delamination or 1140 cycles with a dwell time of 60 min. After the FTF for 1140 cycles, the interface microstructures of each TBC exhibited a sound condition without cracking or delamination. In the TS, the TBCs of 200 and $500{\mu}m$ were fully delaminated (> 50 %) within 171 and 440 cycles, respectively. These results enabled us to control the thickness of TBC systems and to propose an efficient coating in protecting the substrate in cyclic thermal exposure environments.

Diffusion Currents in the Amorphous Structure of Zinc Tin Oxide and Crystallinity-Dependent Electrical Characteristics

  • Oh, Teresa
    • Transactions on Electrical and Electronic Materials
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    • v.18 no.4
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    • pp.225-228
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    • 2017
  • In this study, zinc tin oxide (ZTO) films were prepared on indium tin oxide (ITO) glasses and annealed at different temperatures under vacuum to investigate the correlation between the Ohmic/Schottky contacts, electrical properties, and bonding structures with respect to the annealing temperatures. The ZTO film annealed at $150^{\circ}C$ exhibited an amorphous structure because of the electron-hole recombination effect, and the current of the ZTO film annealed at $150^{\circ}C$ was less than that of the other films because of the potential barrier effect at the Schottky contact. The drift current as charge carriers was similar to the leakage current in a transparent thin-film device, but the diffusion current related to the Schottky barrier leads to the decrease in the leakage current. The direction of the diffusion current was opposite to that of the drift current resulting in a two-fold enhancement of the cut-off effect of leakage drift current due to the diffusion current, and improved performance of the device with the Schottky barrier. Hence, the thin film with an amorphous structure easily becomes a Schottky contact.