• Title, Summary, Keyword: Field emitter

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Fabrication of Carbon Nanotube Field Emitters

  • Yoon, Hyeun-Joong;Jeong, Dae-Jung;Jun, Do-Han;Yang, Sang-Sik
    • Journal of Electrical Engineering and Technology
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    • v.3 no.1
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    • pp.121-124
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    • 2008
  • This paper presents the fabrication and field emission of carbon nanotube field emitters for a micro mass spectrometer. The carbon nanotube is an adequate material as a field emitter since it has good characteristics. We have successfully fabricated a diode field emitter and a triode field emitter. Each field emitter has been constructed using several micromachining processes and a thermal CVD process. In the case of the diode field emitter, to increase the electric field, the carbon nanotubes are selectively grown on the patterned nickel catalyst layer. The electron current of the diode field emitter is 73.2 ${\mu}A$ when the anode voltage is 1100V. That of the triode field emitter is 3.4 pA when the anode voltage is 1000V.

Stablilization of Field Emission Current (Field Emission 전류의 안정화)

  • Yamamoto, Shigehiko
    • Journal of the Korean Vacuum Society
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    • v.2 no.3
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    • pp.335-338
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    • 1993
  • 텅스텐으로 만들어진 field emitter와 탄소로 만들어진 field emitter에서 생기는 step이나 spike 형태의 잡음에 대하여 비교 연구하였다. 그리고 dispenser 형태의 field emiter와 array 형태의 field emitter와 같은 새로운 형태의 field emitter를 설명하였다.

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Field Emission Properties of Carbon Nanotubes on Graphite Tip

  • Shin, Ji-Hong;Shin, Dong-Hoon;Song, Yenan;Sun, Yuning;Lee, Cheol-Jin
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.383-383
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    • 2011
  • Generally, field emitters can be categorized into two types according to the emitter shape, one is a planar field emitter and the other is a point emitter. The planar field emitter is used for displays, flat lamps and signage boards. On the other hands, the point field emitter is expected to play a significant role in x-ray sources and electron beam sources. Such applications of the point field emitters, especially, need large emission current and high emission stability with a small electron beam size. A few reports announced point emitters made by carbon nanotubes (CNTs). However, they still have suffered from poor reproducibility and low emission current. Here, we demonstrated high performance CNT point emitters by attaching CNTs onto graphite rod. Graphite rod exhibited good electrical conductivity and chemical stability. In this method, the shape of the point emitter could be easily controlled by changing the length and diameter of the graphite rod. The CNT point emitter showed emission current over 1 mA at an applied electric field of 1.4 V/${\mu}m$. We consider that the stable emission performance is attributed to the stable contact between CNTs and graphite rod.

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A Carbon Nanotube Field Emitter with a Triode Configuration for a Miniature Mass Spectrometer (초소형 질량분석기를 위한 삼극관 구조의 탄소나노튜브 전자방출원)

  • Lee, Yu-Ri;Lee, Ki-Jung;Hong, Nguyen Tuan;Lee, Soon-Il;Yang, Sang-Sik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.7
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    • pp.1001-1006
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    • 2012
  • This paper presents a carbon nanotube (CNT) triode-structure field emitter as an ion source in a micro time-of-flight mass spectrometer(TOF-MS). In the ion source by field emission, the electrons emitted from cathodes under an electric field accelerated to the anode and ionize gas molecules by impact before arriving the anode. The generated positive ions are to be accelerated to the ion collector. Whereas most of ions are drawn to the cathodes in diode field emitters, a grid in the triode field emitter prevents the ions from being drawn to the cathodes. The triode field emitter is fabricated by micromachining. The cathode is composed of six CNT cylinders. The total size of the fabricated device is $8.0{\times}7.3{\times}1.9mm^3$. The anode and the grid current of the fabricated CNT field emitter were measured for various anode and grid voltages. When the anode and the grid voltages are 1000 V and 990 V, respectively, the emission current passing through the ionization region is 8.6 ${\mu}A$, which is a sufficient emission current for ionization and mass spectrometry.

Relationship of the Distribution Thickness of Dielectric Layer on the Nano-Tip Apex and Distribution of Emitted Electrons

  • Al-Qudah, Ala'a M.;Mousa, Marwan S.
    • Applied Microscopy
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    • v.46 no.3
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    • pp.155-159
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    • 2016
  • This paper analyses the relationship between the distribution of a dielectric layer on the apex of a metal field electron emitter and the distribution of electron emission. Emitters were prepared by coating a tungsten emitter with a layer of epoxylite resin. A high-resolution scanning electron microscope was used to monitor the emitter profile and measure the coating thickness. Field electron microscope studies of the emission current distribution from these composite emitters (Tungsten-Clark Electromedical Instruments Epoxylite resin [Tungsten/CEI-resin emitter]) have been carried out. Two forms of image have been observed: bright single-spot images, thought to be associated with a smooth substrate and a uniform dielectric layer; and multi-spot images, though to be associated with irregularity in the substrate or the dielectric layer.

Simulation of the Strip Type CNT Field Emitter Triode Structure (띠 모양의 에미터를 가지는 탄소나노튜브 삼전극 전계방출 디스플레이 소자의 시뮬레이션)

  • 류성룡;이태동;김영길;변창우;박종원;고성우;천현태;고남제
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.11
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    • pp.1023-1028
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    • 2003
  • The field emission characteristics are studied by simulation for carbon nanotube triode structures with a strip-shaped emitter and a gate hole aligned with it. Two structures, one with double-edge and the other with single edge are analyzed. They show good emission characteristics. Emissions of electrons are concentrated on the edges of emitter and the emitted current increases as the distance between emitter and gate decreases. For single-edged emitter, the emitted electrons form a narow strip-shaped beam which has a good directionality. These triode structures have advantages in that they can be easily fabricated and aligned for assembly.

The Effect of the Guard Ring around the Emitter on the Sensitivity of the Highly Sensitive Separated Drift Field Magnetotransistor (에미터 주위의 guard ring이 분리된 전계를 갖는 고감도 자기 트랜지스터의 민감도에 미치는 영향)

  • Kang, Uk-Song;Lee, Seung-Ki
    • Proceedings of the KIEE Conference
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    • pp.1413-1415
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    • 1994
  • A novel magnetotransistor using a separated drift field with the guard ring around the emitter has been designed and fabricated. The operating principle of the proposed magnetic field sensor is based on the emitter injection modulation. The $p^+$ guard ring around the n-type emitter confines drifted electrons in the emitter, hence the induced Hall voltage in the emitter is increased. The measured relative sensitivity of the separated drift magnetotransistor with the guard ring is about 100 times larger than that without the guard ring.

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The field emission characteristics of an oxidized porous polysilicon field emitter using Pt/Ti emitter-electrode (Pt/Ti 전극을 사용한 산하된 다공질 폴리 실리콘 전계방출소자의 특성)

  • Han Sang-Kug;Park Keun-Yong;Choi Sie-Young
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.6
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    • pp.23-30
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    • 2005
  • In this paper, OPPS(oxidized porous poly-silicon) field emitters were fabricated by using various emitter-electrode metal and these electron emission characteristics were investigated for different thermal annealing effects. The addressed OPPS field emitter with Pt/Ti emitter electrode annealed at $300^{\circ}C$-1hr showed the efficiency of $2.98\%$ at $V_{ps}$=12 V and one annealed at $350^{\circ}C$-1hr showed the highest efficiency of $3.37\%$at $V_{ps}$=16V. They are resulted from the improvement of interfacial contact characteristics of thin emitter metal to an oxidized porous poly-silicon and the decrease of electrical resistance of emitter metal. The brightness of the OPPS field emitter increases linearly in $V_{ps}$ and after oxidation process for $900^{\circ}C$-50min, the brightness of the OPPS field emitter with the as-deposited Pt/Ti emitter electrode was 3600 cd/$m^2$ at the $V_{ps}$=15 V, 6260 cd/$m^2$ at the $V_{ps}$=20 V. Thermal treatment improved the adhesion between the Ti buffer layer and the oxidized porous poly-silicon and also played an important role in the uniform distribution of electric field to the emitter electrode.

Fabrication and Evaluation of electron beam tip for field emission (전계방출 방식의 전자빔 팁의 제작 및 평가)

  • Kim, Chung-Soo;Kim, Dong-Hwan;Park, Man-Jin;Jang, Dong-Young;Ahn, Sung-Hoon;Han, Dong-Chul
    • Proceedings of the KSME Conference
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    • pp.1277-1281
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    • 2007
  • A Nano-tip as a cold field emitter for inducing a field emission current has manufactured in many ways. In the paper, the electrochemical etching method is used. Thus, in order to optimize the final shape as the field emitter, the reliable fabrication system for electrochemical etching was constructed. In addition, the effective parameters such as applied voltage, submerged length, meniscus height, electrolyte concentration and environmental condition(vibration, humidity, cut-off time) have investigated in detail. By controlling the parameters, reliable tungsten tip for field emitter was fabricated. And the fabricated tungsten tip was evaluated optically. Finally, the very sharp apex of the tungsten tip was observed with scanning electron microscope.

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Fabrication and Applications of Comb-Shaped Lateral Field Emitter Arrays (빗살무늬의 수평형 고압전자 방출장치의 구성과 응용)

  • Itoh, Junji
    • Journal of the Korean Vacuum Society
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    • v.2 no.3
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    • pp.331-334
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    • 1993
  • 여러 종류의 수직 또는 수평 형태의 field emitter array가 연구되었다. 그 중 수평형의 FEA는 emitter가 동일 평면 위에 구성되어 있고, gate는 고주파의 응용을 위하여서는 더욱 적합하다. 이 빗살 모양의 FEA의 구조, emission 성질, 응용에 대하여 설명한다.

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