• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.418-423
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• 2010

Carbon nanotubes (CNTs) were synthesized by Fe-catalytic chemical vapor deposition (CVD) method about $800^{\circ}C$. The influence of process parameters such as pretreatment conditions, gas flow ratio, processing time, etc on the growth of CNTs was investigated by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Ammonia was added to acetylene source gas before and during the CNT growth. Different types of CNTs formed depending upon the processing condition. It was found that ammonia prevented amorphous carbons from adsorbing to the outer wall of CNT, resulting in purification of CNTs during CNT growth.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1116-1118
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• 2005

We studied laser crystallization of amorphous silicon films prepared at ultra low temperatures ($<150^{\circ}C$). Amorphous silicon films having a low content of hydrogen were deposited by using catalytic chemical vapor deposition method. Influence of process parameters on the hydrogen content was investigated. Laser crystallization was performed dispensing with the preliminary dehydrogenation process. Crystallization took place at a laser energy density value as low as $70\;mJ/cm^2$, and the grain size increased with increasing the laser energy. The ELA crystallization of Catalytic CVD a-Si film is a promising candidate for Poly-Si TFT in active-matrix flexible display on plastic substrates.

• Korean Journal of Materials Research
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• v.13 no.7
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• pp.424-428
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• 2003

The microstructure and field emission properties of carbon nanotubes(CNT) grown by Ni-catalytic chemical vapor deposition(CVD) were investigated. CVD-grown CNT had a high density of curved shape with randomly oriented. It was found that an increase in electric field caused an increase in field emission current and field emission sites of CNT. The maximum field emission current density was measured to be 3.6 ㎃/$\textrm{cm}^2$ at 2.5 V/$\mu\textrm{m}$, while the brightness of 56 cd/$\textrm{cm}^2$ was observed for the CNT-grown area of 0.8 $\textrm{cm}^2$ from a phosphor screen. Field emission current at constant electric field gradually decreased initially and then stabilized with time.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.247-252
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• 2004

노튜브의 길이는 급격히 증가하였지만 촉매금속의 적층방법에 따른 탄소나노튜브의 성장 형태는 큰 차이가 없었다. 특히, ICBD 방법에 의해 Ni 촉매금속을 증착한 경우 다른 방법에 비하여 직선적인 탄소나노튜브가 관찰되었다. ^x Carbon nanotubes were grown on SiO$_2$/Si substrates by applying $C_2$H$_2$ gas through chemical vapor deposition process. It was found that carbon nanotubes were grown successfully on the substrates with catalytic films under 20 $\AA$ total thickness. The increase in reaction temperature from 50$0^{\circ}C$ to 80$0^{\circ}C$ resulted in longer carbon nanotube, but there was no clear tendencies with different types of catalytic layers. It was evident that carbon nanotubes became more straight on the substrate with Ni catalytic film produced by ICBD method.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1266-1269
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• 2007

Polycrystalline silicon (poly-Si) films were prepared directly on plastic substrates at a low (< $200^{\circ}C$) by using Catalytic Chemical Vapor Deposition (Cat-CVD) technique without subsequent annealing steps. Surface roughness of the poly-Si layer and the density of the gate dielectric layer were found to be influential to the TFT performance.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.7
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• pp.359-363
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• 2006

Single-walled carbon nanotubes (SWCNTs) with few defects and very small amount of amorphous carbon coating have been synthesized by catalytic decomposition of methane in $H_2$ over well-dispersed metal particles supported on MgO. The yield of SWCNTs was estimated to be 88.5% and the purities of SWCNTs thus obtained were more than 90%. Peak of the radial breathing mode in the Raman spectrum demonstrated that the diameters of synthesized CNTs are in the range 0.4-2.0 nm. Our results also indicated that MgO support materials are useful to a large-scale synthesis of high-quality SWCNTs. Increasing temperature could remarkably increase the yield and also improve the quality of SWCNTs from catalytic decomposition of methane. The morphologies and microstructures of the synthesized carbon materials were characterized by scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), Raman spectroscopy, and X-ray diffraction (XRD).

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.383-383
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• 2009

Silicon is commercially prepared by the reaction of high-purity silica with wood, charcoal, and coal, in an electric arc furnace using carbon electrodes, so called the metallurgical refining process, which produces ~98% pure Si (MG-Si). This can be further purified to solar grade silicon (SoG-Si) by various techniques. The most problematic impurity elements are B and P because of their high segregation coefficients. In this study, we explored the possibility of the using Cat-CVD for Si purification. The existing hot-wire CVD was modified to accommodate the catalyzer and the heating source. Mo boat (1.5 cm ${\times}$ 1 cm ${\times}$ 0.2 cm) was used as a heating source. Commercially available Si was purchased from Nilaco corporation (~99% pure). This powder was kept in the Mo-boat and heated to the purification temperature. In addition to the purification by cat-CVD technique, other methods such as thermal CVD, plasma enhanced CVD, vacuum annealing was also tried. It is found that the impurities are reduced to a great extent when treated with cat-CVD method.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.188.2-188.2
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• 2014

Chemical vapor deposition (CVD) method is usually used to grow high-quality large area graphene. In the CVD process, copper is an especially important catalytic-substrate due to the fact that graphene films grown on Cu foils are predominantly one monolayer thick. In this study, we has grown graphene on several types of copper substrates: Cu foils and copper single crystal surfaces such as Cu(100) and Cu(111) are chosen. To investigate the differences between graphene grown on foils and single crystals, we use Raman spectroscopy, X-ray diffraction and atomic force microscopy. Details of the experimental results will be presented.

• Proceedings of the Korea Crystallographic Association Conference
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• 2007.11a
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• pp.7-7
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.132-132
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• 2007