• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.647-651
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• 2004

We fabricated the 1-inch diode type flat lamp using CNTs, which were grown directly on soda-lime glass substrate at 600 ∼ 650 $^{\circ}C$ by thermal chemical vapor deposition(CVD) of acetylene gas. Turn- on field was about 2.8 V/${\mu}{\textrm}{m}$. We observed that uniform and high brightness had been obtained. The brightness of CNT flat lamp was measured up to about 14 kcd/$m^2$ at 2000V in spacing of 500 ${\mu}{\textrm}{m}$. The results showed that the CNTs were very good emission source and suitable for application in the lamp.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.359-361
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• 2007

본 논문은 CNT(Carbon Nano Tube) FEL(Field Emission Lamp)에서 애노드(Anode)-캐소드(Cathode) 구동용 고전압 구동 회로 구현에 관한 것이다. 본 논문에서 제안하는 고전압 DC 전원 회로는 턴비가 높은 고전압 트랜스포머의 Leakage 인덕턴스를 이용하는 Series-Resonant 형태의 Full Bridge 컨버터를 적용하고 고전압 트랜스포머와 Voltage Multiplier를 이용한다. 고전압 트랜스의 절연전압을 줄이기 위해서 두개의 트랜스포머와 Voltage Multiplier를 이용하여 애노드 전극에는 Positive 고전압, 캐소드 전극에는 Negative 고전압을 인가한다. 이 경우 애노드와 캐소드 사이의 아크 방전 시에도 구동 IC 및 스위칭 소자를 보호할 수 있는 장점이 있다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.49-54
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• 2000

A field emission display has spacers separating the emitting base and display face. The arrangement of the spacer is important for maintenance of required clearance, endurance of bending stresses, and efficient vacuum sealing. Topology optimization technique with material density was introduced to select the best position of the spacers from the available positions. The displacement and Von Mises stress distribution of the panels with optimal spacers were calculated by finite element method. Also the design guide for adding eliminating spacers was proposed.

• Journal of the Korean Magnetics Society
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• v.21 no.5
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• pp.163-166
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• 2011

We describe modified Fowler-Nordheim (FN) field emission equation for the free-standing nanomembrane cathode, which has mechanical degrees of freedom. The derived FN equation agrees well with the experimental data. The free-standing nanomambrane cathode demonstrates its unique ability to detect large biomolecure ions.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2258-2261
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• 2010

Since national mid-term target for GHG reduction was determined in 2009, various efforts in transportations have been prepared. Generally, the GHG emission of transportation is calculated using the emission factor published from IPCC guideline(2006). However, it is necessary to develop new emission factors considering the properties of transportation as well as fuel. In Korean railroad, main emission sources are the consumption of diesel and electricity from railcar operation. The GHG emission of electric-powered railcars can be estimated using national electric emission factor, but diesel-powered railcars show different trends. The purpose of this study was to establish the development plans of emission factors for diesel-powered railcars. As a result, the emission factors of diesel-powered railcars were classified into railcar type, engine type and life cycle, notch, load, and traffic volume. In future, several emission factors with this category will be presented quantitatively through field tests with the order of priority.

• Carbon letters
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• v.12 no.4
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• pp.207-217
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• 2011

We discuss the influence of few-walled carbon nanotubes (FWCNTs) treated with nitric acid and/or sulfuric acid on field emission characteristics. FWCNTs/tetraethyl orthosilicate (TEOS) thin film field emitters were fabricated by a spray method using FWCNTs/TEOS sol one-component solution onto indium tin oxide (ITO) glass. After thermal curing, they were found tightly adhered to the ITO glass, and after an activation process by a taping method, numerous FWCNTs were aligned preferentially in the vertical direction. Pristine FWCNT/TEOS-based field emitters revealed higher current density, lower turn-on field, and a higher field enhancement factor than the oxidized FWCNTs-based field emitters. However, the unstable dispersion of pristine FWCNT in TEOS/N,N-dimethylformamide solution was not applicable to the field emitter fabrication using a spray method. Although the field emitter of nitric acid-treated FWCNT showed slightly lower field emission characteristics, this could be improved by the introduction of metal nanoparticles or resistive layer coating. Thus, we can conclude that our spray method using nitric acid-treated FWCNT could be useful for fabricating a field emitter and offers several advantages compared to previously reported techniques such as chemical vapor deposition and screen printing.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.124-127
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• 2000

A new triode type Ti-silicided Si FEA(field emitter array) was realized by Ti-silicidation of Ti coated Si FEA and its field emission properties were investigated. In the fabricated device, the field emission properties through the unit pixel with $200{\mu\textrm{m}}{\times}200{$\mu\textrm{m}}$ tip array in the area of $1000{\mu\textrm{m}}{\times}1000{$\mu\textrm{m}}$ were as follows : the turn-on voltage was about 70V under high vacuum condition of $10^8Torr$, and the field emission current and steady state current degradation were about 2nA/tip and 0.3%/min under the bias of $V_A=500V\;and\;V_G=150V$. The low turn-on voltage and the high current stability during long term operation of the Ti silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• Korean Journal of Materials Research
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• v.10 no.4
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• pp.301-304
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• 2000

A new triode type Co-silicided Si FEA(field emitter array) was realized by Co-silicidation of Co coated Si FEA and its field emission properties were investigated. The field emission properties of the fabricated device through the unit pixel with $45{\times}45$ tip array in the area of $250{\mu\textrm{m}}{\times}250{\mu\textrm{m}}$ under high vacuum condition of $10^{-8}Torr$ were as follows : the turn-on voltage was about 35V and the anode current was about $1.2\mu\textrm{A}(0.6㎁/tip)$ at the bias of $V_A=500V\;and\; V_G=55V$. The fabricated device showed the stable electrical characteristics without degradation of field emission current for the long term operation except for the initial transient state. The low turn-on voltage and the high current stability of the Co-silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• Applied Microscopy
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• v.47 no.1
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• pp.55-62
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• 2017

This paper describes experiments aimed at characterizing the behavior of field electron emitters fabricated by coating carbon fibers with epoxylite resin. Polyacrylonitrile carbon fibers of type VPR-19, thermally treated at $2,800^{\circ}C$, were used. Each was initially prepared in a "uncoated" state, by standard electro polishing and cleaning techniques, and was then examined in a scanning electron microscope. The fiber was then baked overnight in a field electron microscope (FEM) vacuum chamber. Current-voltage characteristics and FEM images were recorded on the following day or later. The fiber was then removed from the FEM, coated with resin, "cured" by baking, and replaced in the FEM. After another overnight bake, the FEM characterization measurements were repeated. The coated fibers had significantly better performance than uncoated fibers. This confirms the results of earlier experiments, and is thought to be due in part to the formation of a conducting channel in the resin over layer. For the coated fiber, lower voltages were needed to obtain the same emission current. The coated fibers have current-voltage characteristics that show smoother trends, with greater stability and repeatability. No switch-on phenomena were observed. In addition, the emission images on the phosphor-coated FEM screen were more concentrated, and hence brighter.

• Korean Journal of Materials Research
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• v.12 no.6
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• pp.499-507
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• 2002

The carbon nanotube emitters for field emission displays were fabricated by using screen printing techniques. The pastes for screen printing are composed of organic binders, carbon nanotubes (multiwalled or singlewalled), and some additive materials. The pastes were printed on Cr-coated/Ag-printed soda-lime glass substrates. From the I-V characteristics, the turn-on field of SWNT was lower than that of MWNT. The decrease in the mesh size of screen masks (i.e. increase in the opening size of the screen mesh) resulted in decreasing the turn-on field and increasing the electron emission current. When the carbon nanotubes were mixed with silver pastes, silver powders appeared to contribute to the vertically aligning of carbon nanotubes on a glass.