• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.31-37
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• 2009

Hybrid ballast for field emission lamp with CNT (carbon nano tube) emitter is proposed. Hybrid ballast consists of a high voltage dc part and hi-polar pulse generation part. Field emission lamp with CNT lamp is composed of three electrodes (anode, gate, and cathode). High voltage dc part is for anode and gate and hi-polar pulse generation part is for gate and cathode in CNT triode respectively. The experimental results demonstrate that the proposed topology is good for driving CNT lamp. To protect the lamp and ballast, OCP (Over Current Protection), OVP (Over Voltage Protection), and OTP (Over Temperature Protection) are added and the experimental results demonstrate that the proposed method is good for driving field emission lamp with CNT emitter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.76-79
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• 2003

The characteristic of single wall carbon nanotube (SW-CNT) and herringbone nano fiber (HB-CNF) emitters was described. SW-CNT synthesized by arc discharge and HB-CNF prepared by thermal CVD were mixed with binders and conductive materials, and then were formed by screen-printing process. In order to obtain efficient field emissions, the surface treatment of rubbing & peel-off was applied to the printed CNT and CNF emitters. The basic structure of FED was of a diode type through fully vacuum packaging. Also, we proposed a new triode type of field emitter using a mesh gate plate having tapered holes and could achieve the ideal triode properties with no gate leakage currents.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.115-119
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• 2011

A tip-type carbon nanotube(CNT)-based field emitter was studied to consider it as electron source for micro-focused x-ray tube. The CNT was grown directly on a metal (tungsten) substrate by using an inductively coupled plasma-chemical vapor deposition (ICP-CVD) method. Prior to CNT growth, the metal substrate was etched to have various tip angles from $10^{\circ}$ to $180^{\circ}C$ (flat-type). The morphologies and microstructures of all the grown CNTs were analyzed via field-emission SEM. Furthermore, the effects of substrate tip-angles on the emission properties of CNT-based field emitters were characterized to estimate the maximum current density, the turn-on voltage, and the spatial distribution of electron beams. Prolonged long-term stability testing of the CNT emitters was also performed. All the experiment results obtained from this study indicated why a tip-type CNT emitter, compared with a flat-type CNT emitter, would be more desirable for a micro-focused x-ray system, in terms of the emission current level, the focused beam area, and the emission stability.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.212-216
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• 2004

In this paper, we have fabricated a triode field emitter using carbon nanotubes (CNTs) directly grown by thermal chemical vapor deposition(CVD) method as an electron omission source. Vertically aligned CNTs have been grown in the center of the gate hole, to the size of 1.5 ${\mu}{\textrm}{m}$ in diameter, with help of a sacrificial layer of a type generally used in metal tip process. By the method of tilling the substrate, we made CNTs emitters both with and without SiO$_2$layer, a sidewall protector, deposited on sidewall of gate. After that we researched the electrical characteristics about two types of emitters. In effect, a sidewall protector can enhance the electrical characteristics by suppressing the problem of short circuits between the gate and the CNTs. The leakage current of an emitter with a sidewall protector is approximately sevenfold lower than that of an emitter without it at a gate voltage of 100 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03b
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• pp.43-43
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• 2010

we have investigated the field emission characteristics of the CNT/TEOS hybrid thin films fabricated by a spray method. It is found that the CNT/TEOS hybrid emitters show high current density, low turn on field, and long-term emission stability compared to the CNT emitters. These efficient field emission characteristics of the CNT/TEOS hybrid emitters are attributed to the TEOS sol, acting as a protection layer of nanotube emitter by surrounding the nanotube tip as well as a binder material to enhance the adhesion of nanotube emitters to the substrate. Therefore, the CNT/TEOS hybrid emitters could be utilized as an alternative for the efficient and reliable field emitters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.181-181
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• 2010

Few-walled carbon nanotubes (FWNTs)-based field emitters with long term stability are fabricated by using a spray method. Tetraethylorthosilicate (TEOS) sol as a binder was mixed with dispersed solution of FWNTs to enhance the adhesion of FWNTs on the cathode substrate. Due to the strong intermolecular interaction of TEOS to the functional groups attached on CNTs and substrate, CNTs are tightly adhered to the cathode electrode when heat treatment is performed at $150^{\circ}C$ for 1 hour, resulting in a stable electron emission of CNT emitters for long time. Excellent field emission characteristics were exhibited, with a large field enhancement factor and low turn-on voltage, comparable to those of CNT emitters fabricated by a screen printing of CNT paste. Therefore, FWNTs / TEOS hybrid films could be utilized as an alternative for the efficient and reliable field emitters.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.384-384
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• 2011

Carbon nanotubes (CNTs) have been studied as an ideal material for field emitters due to the high aspect ratio, excellent electrical property and good mechanical strength. There were many reports on CNT emitters fabricated on rigid substrates, but rare reports about CNT flexible field emitters. Recently, we considered that CNTs can be a good candidate for a flexible field emitter material because of their excellent Young's modulus and elasticity, which could not be achieved with metal tips or semiconducting nanowire tips. In this work, we demonstrated the CNT flexible field emitters fabricated by a simple method and studied the field emission properties of the CNT flexible field emitters under various bending conditions. The flexible field emitters showed stable and uniform emission characteristics. Especially, there is no remarkable change of the field emission properties at the CNT flexible field emitters according to the bending conditions. The CNT flexible field emitters also exhibited a good field emission performance like the low turn-on field and high emission current. Therefore, we suggest that the CNT flexible emitters can be used in many practical applications under different bending conditions.

• Carbon letters
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• v.10 no.3
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• pp.234-238
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• 2009

The field emitters were fabricated by screen-printing of carbon nanotube paste, and their emission stabilities were evaluated. It was found that the emission stability measured in a sealed device is much higher than that measured in a vacuum chamber in spite of similar pressure. This was because oxygen gas was scarcely remained in the sealed device, while the gas is continuously supplied into the vacuum chamber during the stability measurement. It was found that the plasma treatment etched the protruded CNTs, resulting in the uniform height of CNT tips. As a result, the stability was increased remarkably. It was also found that the stability of CNT paste emitter was improved by electrical aging and that the optimum condition for the aging was varied with the size of emitter.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.923-926
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• 2004

Active-matrix field emission display (AMFED) based on carbon nanotube (CNT) emitter and amorphous silicon thin-film transistor (a-Si TFT) is reviewed. The AMFED pixels consisted of a high-voltage a-Si TFT and mesh-gated CNT emitters. The developed AMFED panel showed a high performance with a driving voltage of below 15 V. The low-cost and large-area AMFED approach with a metal mesh technology will be discussed.