• Title/Summary/Keyword: Field Emission

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Properties of Field Emission Electrons for CVD-grown Carbon Nanotubes (CVD법으로 제조한 탄소 나노튜브의 전계 전자 방출 특성)

  • Lee, Rhim-Youl
    • Korean Journal of Materials Research
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    • v.13 no.7
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    • pp.424-428
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    • 2003
  • The microstructure and field emission properties of carbon nanotubes(CNT) grown by Ni-catalytic chemical vapor deposition(CVD) were investigated. CVD-grown CNT had a high density of curved shape with randomly oriented. It was found that an increase in electric field caused an increase in field emission current and field emission sites of CNT. The maximum field emission current density was measured to be 3.6 ㎃/$\textrm{cm}^2$ at 2.5 V/$\mu\textrm{m}$, while the brightness of 56 cd/$\textrm{cm}^2$ was observed for the CNT-grown area of 0.8 $\textrm{cm}^2$ from a phosphor screen. Field emission current at constant electric field gradually decreased initially and then stabilized with time.

Investigation of field emission mechanism of undoped polyucrystalline diamond films

  • Shim, Jae-Yeob;Chi, Eung-Joon;Song, Kie-Moon;Baik, Hong-Koo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.62-62
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    • 1999
  • Carbon based materials have many attractive properties such as a wide band gap, a low electron affinity, and a high chemical and mechanical stability. Therefore, researches on the carbon-based materials as field emitters have been drawn extensively to enhance the field emission properties. Especially, diamond gives high current density, high current stability high thermal conductivity durable for high temperature operation, and low field emission behaviors, Among these properties understanding the origin of low field emission is a key factor for the application of diamond to a filed emitter and the verification of the emission site and its distribution of diamond is helpful to clarify the origin of low field emission from diamond There have been many investigations on the origin of low field emission behavior of diamond crystal or chemical vapor deposition (CVD) diamond films that is intentionally doped or not. However, the origin of the low field emission behavior and the consequent field emission mechanism is still not converged and those may be different between diamond crystal and CVD diamond films as well as the diamond that is doped or not. In addition, there have been no systematic studies on the dependence of nondiamond carbon on the spatial distribution of emission sites and its uniformity. Thus, clarifying a possible mechanism for the low field emission covering the diamond with various properties might be indeed a difficult work. On the other hand, it is believed that electron emission mechanisms of diamond are closely related to the emission sites and its distributions. In this context, it will be helpful to compare the spatial distribution of emission sites and field emission properties of the diamond films prepared by systematic variations of structural property. In this study, we have focused on an understanding of the field emission variations of structural property. In this study, we have focused on an understanding of the field emission mechanism for the CVD grown undoped polycrystalline diamond films with significantly different structural properties. The structural properties of the films were systematically modified by varying the CH4/H2 ratio and/or applying positive substrate bias examined. It was confirmed from the present study that the field emission characteristics are strongly dependent on the nondiamond carbon contents of the undoped polycrystalline diamond films, and a possible field emission mechanism for the undoped polycrystalline diamond films is suggested.

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A Reliable Field Emission Performance of Double-Walled Carbon Nanotube Field Emitters (이중층 탄소나노튜브 전계전자 방출원의 신뢰성 있는 전계방출 특성)

  • Jung, S.I.;Lee, S.B.
    • Journal of the Korean Vacuum Society
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    • v.17 no.6
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    • pp.566-575
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    • 2008
  • We investigated the field emission characteristics from the planar field emitters made of double-walled carbon nanotubes (DWCNTs) synthesized by a catalytic chemical vapor deposition (CCVD) method. Transmission electron microscopy, Thermogravimetric and Raman analysis showed that the carbon materials have a low defect level in their atomic carbon structure, pointing to the synthesis of high-purity DWCNTs. For field emission properties of DWCNTs, the turn-on field of DWCNTs was $1.9\;V/{\mu}m$ and the current density was about $74\;mA/cm^2$ at $8.1\;V/{\mu}m$, which is sufficient for the applications of field emission displays and vacuum microelectronic devices. The DWCNT field emitters also exhibited a uniform field emission pattern and good field emission stability in a diode configuration.

Enhancement of Field Emission Characteristics of CuO Nanowires Formed by Wet Chemical Process (습식공정으로 형성된 구리산화물 나노와이어의 전계방출특성 향상)

  • Sung Woo-Yong;Kim Wal-Jun;Lee Seung-Min;Lee Ho-Young;Park Kyung-Ho;Lee Soonil;Kim Yong-Hyup
    • Journal of the Korean institute of surface engineering
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    • v.37 no.6
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    • pp.313-318
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    • 2004
  • Vertically-aligned and uniformly-distributed CuO nanowires were formed on copper-coated Si substrates by wet chemical process, immersing them in a hot alkaline solution. The effects of hydrogen plasma treatment on the field emission characteristics of CuO nanowires were investigated. It was found that hydrogen plasma treatment enhanced the field emission properties of CuO nanowires by showing a decrease in turn-on voltage, and an increase in emission current density, and stability of current-voltage curves. However, the excessive hydrogen plasma treatment made the I-V curves unstable. It was confirmed by XPS (X-ray Photoelectron Spectroscopy) analysis that hydrogen plasma treatment deoxidized CuO nanowires, thereby the work function of the nanowires decreased from 4.35 eV (CuO) to 4.1 eV (Cu). It is thought that the decrease in the work function enhanced the field emission characteristics. It is well-known that the lower the work function, the better the field emission characteristics. The results suggest that the hydrogen plasma treatment is very effective in achieving enhanced field emission properties of the CuO nanowires, and there may exist an optimal hydrogen plasma treatment condition.

Thermo-Field emission in silicon nanomembrane ion detector for mass spectrometry (실리콘 나노 박막의 열-전계 방출효과를 이용한 분자 질량분석)

  • Park, Jong-Hoo
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.4
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    • pp.586-591
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    • 2013
  • This paper describes the characteristics of thermo-field emission in a freestanding silicon nanomembrane under ion bombardment with various thermal and field conditions. The thermal effect and field effect in thermo-field emission in silicon nanomembrane are investigated by varying kinetic energy of ions and electric field applied to the silicon nanomembrane surface, respectively. We found that thermo-field emission increases linearly as the electric field increases, when the electric field intensity is lower than the threshold. The thermo-field emission (schottky effect) increases proportionally to the power of temperature, which agree well with the predictions of a thermo-field emission model.

Field emission characteristics of carbon nanfiber bundles

  • Kim, Sung-Hoon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.14 no.5
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    • pp.211-214
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    • 2004
  • Carbon nanofiber bundles were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition system. These bundles were vertically well-grown under the high negative bias voltage condition. The bundles were composed of the individual carbon nanofiber having less than 100 nm diameters. Turn-on voltage of the field emission was measured around 0.8 V/$\mu\textrm{m}$. Fowler-Nordheim plot of the measured values confirmed the field emission characteristic of the measured current.

Dispersion of carbon nanotube in polymer composite and their field emission superiority

  • Park, J.H.;Jeon, S.Y.;Alegonkar, P.S.;Yoo, J.B.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.778-781
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    • 2007
  • The dispersion of carbon nanotubes in composite and their field emission superiority have been discussed. Four synthesis methods have been studied. The CNT-composite, synthesized by the combination of the chemical and mechanical dispersion routes shows superior dispersion as well as field emission characteristics as compared to other syntheses methods.

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Pt nanoparticles-coated Carbon nanofiber for FED application

  • Lee, Won-Woo;Choi, Young-Min;Ryu, Beyong-Hwan
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1590-1592
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    • 2007
  • In this study, we prepared CNF (carbon nanofiber) by the solvothermal method for FED (field emission display) applications. We controlled several conditions to synthesize effective CNF for field emission applications. Nano-sizesd Pt nanoparticles were coated on the CNF. In this study, we have applied Pt nanoparticles- coated CNF which can be produced in mass, to field emission application.

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Development of Tubeless-Packaged Field Emission Display (Tubeless Packaging된 Field Emission Display의 개발)

  • Ju, Byeong-Gwon;Lee, Deok-Jung;Lee, Yun-Hui;O, Myeong-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.4
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    • pp.275-280
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    • 1999
  • The glass-to-glass electrostatic bonding process in vacuum environment was developed and the tubeless-packaged FED was fabricated based on the bonding process. The fabricated tubeless-packaged FED showed stable field emission characteristics and potential applicability to the FED tubeless packaging and vacuum in-line sealing.

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