• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.150-150
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• 2010

Carbon nanotubes have drawn attention as one of the most promising emitter materials ever known not only due to their nanometer-scale radius of curvature at tip and extremely high aspect ratios but also due to their strong mechanical strength, excellent thermal conductivity, good chemical stability, etc. Some applications of CNTs as emitters, such as X-ray tubes and microwave amplifiers, require high current emission over a small emitter area. The field emission for high current density often damages CNT emitters by Joule heating, field evaporation, or electrostatic interaction. In order to endure the high current density emission, CNT emitters should be optimally fabricated in terms of material properties and morphological aspects: highly crystalline CNT materials, low gas emission during electron emission in vacuum, optimal emitter distribution density, optimal aspect ratio of emitters, uniform emitter height, strong emitter adhesion onto a substrate, etc. We attempted a novel approach to fabricate CNT emitters to meet some of requirements described above, including highly crystalline CNT materials, low gas emission, and strong emitter adhesion. In this study, CNT emitters were fabricated by filtrating an aqueous suspension of highly crystalline thin multiwalled CNTs (Hanwha Nanotech Inc.) through a metal mesh. The metal mesh served as a support and fixture frame of CNT emitters. When 5 ml of the CNT suspension was engaged in filtration through a 400 mesh, the CNT layers were formed to be as thick as the mesh at the mesh openings. The CNT emitter sample of $1{\times}1\;cm^2$ in size was characteristic of the turn-on electrical field of 2.7 V/${\mu}m$ and the current density of 14.5 mA at 5.8 V/${\mu}m$ without noticeable deterioration of emitters. This study seems to provide a novel fabrication route to simply produce small-size CNT emitters for high current emission with reliability.

• Current Photovoltaic Research
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• v.3 no.3
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• pp.80-84
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• 2015

We suggest new emitter formation method using solid-phase epitaxy (SPE); solid-phase epitaxy emitter (SEE). This method expect simplification and cost reduction of process compared with furnace process (POCl3 or BBr3). The solid-phase epitaxy emitter (SEE) deposited a-Si:H layer by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) on substrate (c-Si), then thin layer growth solid-phase epitaxy (SPE) using rapid thermal process (RTP). This is possible in various emitter profile formation through dopant gas ($PH_3$) control at deposited a-Si:H layer. We fabricated solar cell to apply solid-phase epitaxy emitter (SEE). Its performance have an effect on crystallinity of phase transition layer (a-Si to c-Si). We confirmed crystallinity of this with a-Si:H layer thickness and annealing temperature by using raman spectroscopy, spectroscopic ellipsometry and transmission electron microscope. The crystallinity is excellent as the thickness of a-Si layer is thin (~50 nm) and annealing temperature is high (<$900^{\circ}C$). We fabricated a 16.7% solid-phase epitaxy emitter (SEE) cell. We anticipate its performance improvement applying thin tunnel oxide (<2nm).

• Journal of Information Display
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• v.1 no.1
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• pp.63-69
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• 2000

In order to improve both the level and the stability of electron emission, Mo and Co silicides were formed from Mo mono-layer and Ti/Co bi-layers on single crystal silicon field emitter arrays (FEAs), respectively. Using the slope of Fowler-Nordheim curve and tip radius measured from scanning electron microscopy (SEM), the effective work function of Mo and Co silicide FEAs were calculated to be 3.13 eV and 2.56 eV, respectively. Compared with silicon field emitters, Mo and Co silicide exhibited 10 and 34 times higher maximum emission current, 10 V and 46 V higher device failure voltage, and 6.1 and 4.8 times lower current fluctuation, respectively. Moreover, the emission currents of the silicide FEAs depending on vacuum level were almost the same in the range of $10^{-9}{\sim}10^{-6}$ torr. This result shows that silicide is robust in terms of anode current degradation due to the absorption of air molecules.

• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.113-118
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• 1996

Aligning a cathode tip at the center of a gate hole is important in gated filed emission devices. We have fabricated a silicon field emitter using a following process so that a cathode and a gate hole are automatically aligned . After forming silicon tips on a silicon wafer, the wafer was covered with the $SiO_2$, gate metal, and photoresistive(PR) films. Because of the viscosity of the PR films, a spot where cathode tips were located protruded above the surface. By ashing the surface of the PR film, the gate metal above the tip apex was exposed when other area was still covered with the PR film. The exposed gate metal and subsequenlty the $SiO_2$ layer were selectively etched. The result produced a field emitter in which the gate film was in volcano shape and the cathode tip was located at the center of the gate hole. Computer simulation showed that the volcano shape and the cathode tip was located at the center of the gat hole. Computer simulation showed that the volcano shape emitter higher current and the electron beam which was focused better than the emitter for which the gate film was flat.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1408-1409
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• 2011

Carbon nanotubes (CNTs) were grown on conical tip substrates by using various methods such as electrophoretic deposition, dip-coating, and spray. The scanning electron microscope measurement showed that the spray method ascertained the most uniform deposition of CNTs. The CNT-emitter that was fabricated by the spray method revealed the lowest turn on voltage of electron emission and the highest emission current. In addition, the spray-produced CNT emitter showed the most stable long-term emission characteristics.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1410-1411
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• 2011

Tip-type carbon nanotube(CNT) based electron emitters were fabricated by forming a hafnium(Hf) interlayer between the CNT and the substrate. The CNTs were deposited by using the electrophoretic deposition method and thermally treated. No significant change in the microscopic structure of the CNTs, such as the ratio of length to diameter, was observed after the deposition of Hf interlayer and thermal treatment. As compared with the CNT emitter without the Hf-interlayer and thermal treatment, the CNT emitter with the Hf-interlayer and thermal treatment showed noticeably improved electron-emission properties due to the enhanced adhesion.

• Transactions on Electrical and Electronic Materials
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• v.17 no.5
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• pp.306-309
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• 2016

The Cs₃Sb photocathode was formed by non-vacuum process technology. An in-situ vacuum device was fabricated successively with flat cesium antimonide photocathode emitters fabricated in a process chamber. The electrical properties of the device were characterized. Electron emission from the devices was induced by photoemitted electrons, which were accelerated by an anode electric field that was shielded from the photoemitter surface. The electrical characteristics of the devices were investigated by measuring the anode current as a function of device operation times with respect to applied anode voltages. Planar blue LED light with a 450 nm wavelength was used as an excitation source. The results showed that the cesium antimonide photocathode emitter has the potential of long lifetime with stable electron emission characteristics in panel devices. These features demonstrate that the cesium antimony photocathodes produced by non-vacuum processing technology is suitable for flat cathodes in panel device applications.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.789-791
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• 1998

Numerical simulation has been performed on a microtip field emitter structure produced by employing a CMP technology. The field distributions are estimated by using a Maxwell 2D vector simulator and the electron trajectories are obtained by solving the equation of ballistic motion of emitted electrons. The beam width observed at the phosphor has been characterized as a function of the applied voltages and the gate-to-tip distance. It has also been investigated how the electron trajectory is changed by adopting the anode switching as well as the focus electrode.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.270-273
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• 2006

In this study, ink-jet technology is applied to the emitter fabrication for surface-conduction electron-emitter display (SED). The general emiiter material of SED, palladium oxide (PdO), is prepared by calcination the mixture of solvent and precursors of platinum chlorine and platinum nitrate. With controlling the precursors and solvents, the PdO is formed below $400^{\circ}C$ which is required for SED process.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1016-1019
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• 2005

We studied the density control of carbon nanotubes (CNTs) which were grown on the iron nanoparticles prepared from iron-acetate [$Fe(II)(CH_3COO)_2$] solution using freeze-dry method. The density of CNTs was controlled for the enhancement of field emission. The patterning process of iron-acetate catalyst-layer for the fabrication of electronic device was simply achieved by using alkaline solution, TMAH (tetramethylammonium hydroxide). We applied this patterning process of catalyst layer to formation of the electron emitter with under gate type triode structure.