• Title/Summary/Keyword: Nano-Electronics

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Electrochemical Characteristics of supercapacitor using organic-inorganic electrode (유-무기 복합전극을 이용한 수퍼커패시터의 전기화학적 특성)

  • Kim, Hong-Il;Kim, Sang-Gil;Yuk, Gyung-Chang;Park, Soo-Gil
    • Proceedings of the KIEE Conference
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    • 2002.11a
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    • pp.164-166
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    • 2002
  • Over the past two decades, the electrochemical supercapaictors are receiving growing attention due to their possible applications as power backup in electronic equipment and electrical vehicles. Both of amorphous cobalt oxide and manganese dioxide were prepared by sol-gel process reported in our previous work. Nano-structured supramolecular oligomer of 1,5-diamino anthraquinone(DAAQ) coated metal oxides were successfully prepared by electrochemical oxidation from an acidic non-aqueous medium. We established process parameters of the technique for the formation of nano-structured materials. Furthermore, improved the capacitive properties of the nano structured metal oxide electrodes using controlled solution chemistry. $CoO_2$ and $MnO_2$-based composite electrode showed relatively good electrochemical behaviors in acidic electrolyte system with respect to specific capacity and scan rate dependency

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Synthesis and Properties of Ca8Gd2(PO4)6O2 Nano-Crystalline Structures

  • Bharat, L. Krishna;Yu, Jae Su
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.286.1-286.1
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    • 2013
  • Nowadays, the glare towards the light-emitting diode (LED) lighting source has much attention due to its eco-friendly nature, reduced energy consumption, and low CO2 emission. LEDs can show versatile colors by changing the composition ratio of semiconductors. Phosphors re-emit light by absorbing light from LED, which is the key factor for emission. The endeavor to make replica of natural white light is increasing day by day. Industrially, blue LED chip crowned with a yellow phosphor coated lens gives low quality white light. Newly, many researchers are introducing modern approaches, adding red phosphor to the yellow phosphor to increase the quality of white light. Here, we synthesized structurally and chemically stable europium doped oxyapatite Ca8Gd2(PO4)6O2 nano-crystalline structures by a hydrothermal method. The ultrafine structures were formed due to the effect of ethylenediaminetetraacetic acid, which is confirmed by the transmission electron microscope images. The structural properties were analyzed using the X-ray diffraction patterns.

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Nonvolatile Memory Characteristics of Double-Stacked Si Nanocluster Floating Gate Transistor

  • Kim, Eun-Kyeom;Kim, Kyong-Min;Son, Dae-Ho;Kim, Jeong-Ho;Lee, Kyung-Su;Won, Sung-Hwan;Sok, Jung-Hyun;Hong, Wan-Shick;Park, Kyoung-Wan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.8 no.1
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    • pp.27-31
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    • 2008
  • We have studied nonvolatile memory properties of MOSFETs with double-stacked Si nanoclusters in the oxide-gate stacks. We formed Si nanoclusters of a uniform size distribution on a 5 nm-thick tunneling oxide layer, followed by a 10 nm-thick intermediate oxide and a second layer of Si nanoclusters by using LPCVD system. We then investigated the memory characteristics of the MOSFET and observed that the charge retention time of a double-stacked Si nanocluster MOSFET was longer than that of a single-layer device. We also found that the double-stacked Si nanocluster MOSFET is suitable for use as a dual-bit memory.

Artificial Vision Project by Micro-Bio Technologies

  • Kim Sung June;Jung Hum;Yu Young Suk;Yu Hyeong Gon;Cho Dong il;Lee Byeong Ho;Ku Yong Sook;Kim Eun Mi;Seo Jong Mo;Kim Hyo kyum;Kim Eui tae;Paik Seung June;Yoon Il Young
    • 한국가시화정보학회:학술대회논문집
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    • 2002.04a
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    • pp.51-78
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    • 2002
  • A number of research groups worldwide are studying electronic implants that can be mounted on retinal optic nerve/visual cortex to restore vision of patients suffering from retinal degeneration. The implants consist of a neural interface made of biocompatible materials, one or more integrated circuits for stimuli generation, a camera, an image processor, and a telemetric channel. The realization of these classes of neural prosthetic devices is largely due to the explosive development of micro- and nano-electronics technologies in the late $20^{th}$ century and biotechnologies more recently. Animal experiments showed promise and some human experiments are in progress to indicate that recognition of images can be obtained and improved over time. We, at NBS-ERC of SNU, have started our own retinal implant project in 2000. We have selected polyimide as the biomaterial for an epi-retinal stimulator. In-vitro and in-vivo biocompatibility studies have been performed on the electrode arrays. We have obtained good affinity to retinal pigment epithelial cells and no harmful effect. The implant also showed very good stability and safety in rabbit eye for 12 weeks. We have also demonstrated that through proper stimulation of inner retina, meaning vision can be obtained.

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Effect of PVP(polyvinylpyrrolidone) on the Ag Nano Ink Property for Reverse Offset Printing (PVP(polyvinylpyrrolidone)가 리버스 오프셋용 은 나노 잉크 물성에 미치는 영향)

  • Han, Hyun-Suk;Kwak, Sun-Woo;Kim, Bong-Min;Lee, Taik-Min;Kim, Sang-Ho;Kim, In-Young
    • Korean Journal of Materials Research
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    • v.22 no.9
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    • pp.476-481
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    • 2012
  • Among the various roll-to-roll printing technologies such as gravure, gravure-offset, and reverse offset printing, reverse offset printing has the advantage of fine patterning, with less than 5 ${\mu}m$ line width. However, it involves complex processes, consisting of 1) the coating process, 2) the off process, 3) the patterning process, and 4) the set process of the ink. Each process demands various ink properties, including viscosity, surface tension, stickiness, and adhesion with substrate or clich$\acute{e}$; these properties are critical factors for the printing quality of fine patterning. In this study, Ag nano ink was developed for reverse offset printing and the effect of polyvinylpyrrolidone(PVP), used as a capping agent of Ag nano particles, on the printing quality was investigated. Ag nano particles with a diameter of ~60 nm were synthesized using the conventional polyol synthesis process. Ethanol and ethylene glycol monopropyl ether(EGPE) were used together as the main solvent in order to control the drying and absorption of the solvents during the printing process. The rheological behavior, especially ink adhesion and stickiness, was controlled with washing processes that have an effect on the offset process and that played a critical role in the fine patterning. The electrical and thermal behaviors were analyzed according to the content of PVP in the Ag ink. Finally, an Ag mesh pattern with a line width of 10 ${\mu}m$ was printed using reverse offset printing; this printing showed an electrical resistivity of 36 ${\mu}{\Omega}{\cdot}cm$ after sintering at $200^{\circ}C$.

Fringe Field Effects on Transient Characteristics of Nano-Electromechanical (NEM) Nonvolatile Memory Cells

  • Han, Boram;Choi, Woo Young
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.5
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    • pp.609-614
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    • 2014
  • The fringe field effects on the transient characteristics of nano-electromechanical (NEM) memory cells have been discussed by using an analytical model. The influence of fringe field becomes stronger as the size of a cell decreases. By using the proposed model, the dependency of NEM memory transient characteristics on cell parameters has been evaluated.

The Reliability Evaluation about the Triode-Type CNT Emission Source (삼극형 CNT 전자원에 대한 신뢰성 평가)

  • Kang, J.T.;Kim, D.J.;Jeong, J.W.;Kim, D.I.;Kim, J.S.;Lee, H.R.;Song, Y.H.
    • Journal of the Korean Vacuum Society
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    • v.18 no.2
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    • pp.79-84
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    • 2009
  • The electron emission source of triode type has been fabricated using CNT paste. The nano Ag particle and photosensitive polymers were added to the CNT paste. The surface roughness of the CNT emitter was uniform by the back exposure method. The added nano Ag particle improves the adhesion and the electric conductance with small variation in the CNTs and between electrode. After the aging with heat-exhausting, the reliability of the triode CNT electron source was secured in the high voltage and current operation for 12 hours. At this time, the gate leakage current was about 10 % less than.

Fabrication of Monolithic Spectrometer Module Based on Planar Optical Waveguide Platform using UV Imprint Lithography (UV 임프린트 공정을 이용한 평판형 광도파로 기반의 집적형 분광 모듈 제작)

  • Oh, Seung hun;Jeong, Myung yung;Kim, Hwan gi;Choi, Hyun young
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.3
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    • pp.73-77
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    • 2015
  • This paper presents integrated polymeric spectrometer module which offers compact size, easily-fabricated structure and low cost. The proposed spectrometer module includes the nano diffraction grating with non-uniform pitch and planar optical waveguide with concave mirror to be fabricated by UV imprint lithography. To increase the reflection efficiency, we designed the nano diffraction grating with triangular profiles. The polymeric planar spectrometer includes a spectral bandwidth of 700 nm, resolution of 10 nm and precision below 5 nm. This polymeric planar spectrometer is well-suited for sensor system.

A Study on the Soldering Characteristic of 4 Bus Bar Crystalline Silicon Solar Cell on Infrared Lamp and Hot Plate Temperature Control (적외선 램프 및 핫 플레이트 온도 제어를 통한 4 Bus Bar 결정질 실리콘 태양전지 솔더링 특성에 관한 연구)

  • Lee, Jung Jin;Son, Hyoung Jin;Kim, Seong Hyun
    • Current Photovoltaic Research
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    • v.5 no.3
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    • pp.83-88
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    • 2017
  • The growth of intermetallic compounds is an important factor in the reliability of solar cells. Especially, the temperature change in the soldering process greatly affects the thickness of the intermetallic compound layer. In this study, we investigated the intermetallic compound growth by Sn-diffusion in solder joints of solar cells. The thickness of the intermetallic compound layer was analyzed by IR lamp power and hot plate temperature control, and the correlation between the intermetallic compound layer and the adhesive strength was confirmed by a $90^{\circ}$ peel test. In order to investigate the growth of the intermetallic compound layer during isothermal aging, the growth of the intermetallic compound layer was analyzed at $85^{\circ}C$ and 85% for 500 h. In addition, the activation energy of Sn was calculated. The diffusion coefficient of the intermetallic compound layer was simulated and compared with experimental results to predict the long-term reliability.