• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.723-730
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• 2003

The CN(carbon nitrogen) nanofibers were formed by HIP(high isostatic pressure) process. From the field emission measurement, CN nanofibers shows an excellent characteristics of emitter, better than CNTs and carbon nanofibers. The structures obtained can be divided into three groups : bamboo-like fibers, corrugated structures and bead necklace-like fib res. Emission properties of CN nanofibers were investigated for spacing, between anode and cathode, variation. Turn-on fields was 1.4 v/$\mu\textrm{m}$. The time reliability and light emission test were carried out for about 100 hours. We suggest that CN nanofibers can be possibly applied to the high brightness flat lamp because of low turn-on field and time reliability

• 한국재료학회지
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• 제17권3호
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• pp.173-178
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• 2007

Carbon nanotube cathodes(CNT cathodes) with a trench structure similar to gated structure of triode-type cathode were fabricated by a screen printing method using multi-walled carbon nanotubes. The effects of surface treatments on CNT cathodes were investigated for high efficiency field emission displays(FEDs). A liquid method easily removed the organic residue and protruded the CNTs. Field emission properties were measured by using a diode-type mode. The liquid method produced a turn-on field of $1.4V/{\mu}m$. The emission current density was measured about $3.1mA/cm^{2}$ at the electric field of $3V/{\mu}m$. The liquid method showed a high potential applicable to the surface treatment for triode-type FEDs.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.179.1-179.1
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• 2013

Cylindrical Rotating Magnetron Sputtering Cathode (이하 Rotary Cathode)는 기존에 사용 되던 rectangular type 보다 Target 사용 효율이 높다는 큰 이점을 가지고 있다. 높은 Target 사용 효율은 비용 절감 효과와 직접적으로 관련 된다. 이번 연구는 3D Plasma simulation(PIC-MCC)을 통한 Target 사용 효율 80% 이상의 Rotary Cathode 개발을 목적으로 한다. Plasma simulation에 External Magnetic fields를 접목하여 Electron의 이동 궤적을 제어하였고, 생성된 Ion (Ar+)의 밀도 및 속도로 Plasma의 안정성과 Erosion 계산 구간을 선정 하였다. Target Erosion Profile은 Sputtering yield Data와 Target에 충돌한 Ion 정보를 사용하여 산출 하였으며, Sputtered Particles의 Deposition Profile은 계산된 Target Erosion Profile과 The cosine law of emission을 이용하여 계산 하였다. 실험 조건은 Plasma simulation의 초기조건 바탕으로 하여 2G size의 ITO Target을 대상으로 실험 하였다. 비 Erosion 영역 최소화하기 위해 Magnet Length를 변경하여 제작 적용 하였다. Simulation 계산 시간의 제약으로 인하여 simulation에서 생성된 최대 이온 밀도는 일반적으로 알려진 값 보다 적게 계산 되었지만, Simulation으로 예측한 Erosion Profile 및 Deposition Profile은 실험 값과 유사한 형태를 나타났으며, 실험 결과는 Target 사용 효율 80%이상의 결과를 보였다.

• Applied Microscopy
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• 제47권3호
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• pp.86-94
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• 2017

In this study, we will describe a new design of carbon nanotubes tip. Single-walled carbon nanotubes produced using high-pressure CO over Fe particles (HiPCO) at CNI, Houston, TX used in this study. These tips were manufactured by employing a drawing technique using glass puller. Field electron microscopies with tips (cathode) to screen (Anode) separation of ~10 mm was used to characterize the electron emitters. The system was evacuated down to base pressure of (${\sim}10^{-8}$ mbar) when baked at up to (${\sim}200^{\circ}C$) over night. An electron field emission patterns, as well as current versus voltage characteristics and Fowler-Nordheim plots, are discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.60-63
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• 2004

Recently, carbon nanotubes(CNTs) have been demonstrated to possess remarkable mechanical and electronic properties, in particular, for field emission applications. Its high aspect ratio and extremely small diameter, hollowness, together with high mechanical strength and high chemical stability, are advantages for use in field emitter. In this paper, we demonstrate electrical discharge properties from carbon nanotube cathode electrodes to use as an emitter electrode of vacuum gauges. Vertically aligned $2{\times}2mm^2$ CNT arrays on the silicon substrate were synthesized by the thermal CVD method on Fe catalytic metal, and a glass patterning by the sand blast method and the silicon/glass anodic bonding processes were applied to make samples with 2 electrodes. The field emission was examined under the vacuum range of $10^{-3}$ Torr.

• 전기의세계
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• 제30권3호
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• pp.172-176
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• 1981

The reduction in the breakdown field strength due to electrode surface roughness was calculated by applying the streamer breakdown criterion and the surface roughness factor, and measurements of static breakdown voltage for a gap with an artificial protrusion were made under the uniform field at pressures up to 4 bar in pressurized $SF_{6}$. The effect of polarity of highly stressed electrode on the breakdown field strength was also investigated. The measurements have shown that the measured breakdown levels for a protrusion located on the cathode agree with those calculated and the values measured with an identical anode protrusion are substantially higher and more scattered. This may be explained if it assumed that a high rate of production of initiatory electrons is maintained at the tip of a cathode protrusion by field emission. In practical point of view, the breakdown levels in pressurized $SF_{6}$ can be bereliably estimated from the values calculated.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.26-31
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• 2016

The Townsend to glow discharge mode transition was investigated in the dielectric barrier discharge (DBD) helium plasma source which was powered by 20 kHz / $4.5 kV_{rms}$ high voltage at atmospheric pressure. The spatial profile of the electric field strength at each modes was measured by using the intensity ratio method of two helium emission lines (667.8 nm ($3^1D{\rightarrow}2^1P$) and 728.1 nm ($3^1S{\rightarrow}2^1P$)) and the Stark effect. ICCD images were analyzed with consideration for the electric field property. The Townsend discharge (TD) mode at the initial stage of breakdown has the light emission region located in the vicinity of the anode. The electric field of the light emitting region is close to the applied field in the system. Immediately, the light emitting region moves to the cathode and the discharge transits to the glow discharge (GD) mode. This mode transition can be understood with the ionization wave propagation. The electric field of the emitting region of GD near cathode is higher than that of TD near anode because of the cathode fall formation. This observation may apply to designing a DBD process system and to analysis of the process treatment results.

• 대한금속재료학회지
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• 제48권2호
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• pp.180-186
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• 2010

For the application of field emission display (FED), it is essential to develop a carbon nanotube (CNT) cathode with high emission current density. In this study, we developed and demonstrated a post-heat treatment (PHT) process to improve field emission properties of CNT cathodes. Since the PHT is intended to burn out organic materials covering the CNTs, the PHT was carried out by heating samples at a high temperature in an atmosphere. The PHT process is applied for samples processed by surface treatment with an adhesive tape. Compared to samples prior to the PHT, samples after the PHT at $360^{\circ}C$ showed about 17% improvement in emission current density. The major reason for the increased current density is mainly the increased aspect ratio of the CNTs because of the removal of the adhesive organic residues covering the CNTs, which were attached on the CNT surfaces during the surface treatment using the adhesive taping method.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.300-305
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• 2004

A preliminary study on. field emitter array cathodes was conducted aiming at applying for electrodymanic tether (EDT) propulsion systems. The EDT propulsion systems are assumed to use for active removal systems of post-mission spacecraft, which would otherwise become space debris. A survey on field emit-ter array cathode technology was conducted, and it showed that carbon nanotube (CNT) emitters are suit-able to EDT application. Trial fabrications and evaluation tests of CNT emitters were conducted, which demonstrated a target emission current density of 10 ㎃/$\textrm{cm}^2$. It was found out that the most important technical issue for developing CNT emitters is to improve the performance against voltage breakdown between the emitter and the opposite electrode.

• 한국표면공학회지
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• 제41권3호
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• pp.94-101
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• 2008

A new convenient magnet array module is designed to investigate effects of magnetic field array on magnetron discharge characteristics. Magnetic field analysis showed good agreement of measured discharge region by a CCD device which has a high quantum efficiency over visible wavelength range. OES (optical emission spectroscopy) showed major emission peaks are from electronic transitions in 400 nm range and 800 nm range. Effects of driving voltage characteristics were analyzed in a point of electron drift trajectories and ionizing collision frequencies. Pulsed dc with a fast rising and falling time was analyzed to have potential to increase ionization collisions by putting a burst of hot electrons and to raise sheath potential. From measured voltage and current waveform, maximum of -1000 V peak was generated with $-400\;V_{rms}$ conditions. Possibility of a properly designed magnetron cathode was shown to be used as a melting device. Cu was successfully melted with power density of a several tens of $W/cm^2$.