• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.299-309
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• 2016

In this study, the physicochemical and electrochemical properties of carbon nanomaterials and synthesized nano-carbon/Si composites were studied. The nano-carbon/Si composites were ball-milled to a nano size and coated with pyrolytic carbon using Chemical Vapor Deposition (CVD). They were then finely mixed with respective nano-carbon materials. The physicochemical properties of samples were analyzed using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Raman spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and surface area analyzer. The electrochemical characteristics were investigated using the galvanostatic charge-discharge and cyclic voltammetry (CV) measurements. Three-electrode cells were fabricated using the carbon nanomaterials and nano-carbon/Si composites as anode materials and LiPF₆ and LiClO₄ as electrolytes of Li secondary batteries. Reversibility using LiClO₄ as an electrolyte was superior to that of LiPF₆ as the electrolyte. The initial discharge capacities of nano-carbon/Si composites were increased compared to the initial discharge capacities of nano-carbon materials.

• Journal of the Korean Applied Science and Technology
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• v.21 no.1
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• pp.45-50
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• 2004

The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst. Reaction temperatures were changed from 600 to $850^{\circ}C$, and reactants flow rates were changed from 100 to 200 mL/mim. There were no significant changes in the methane conversion observed in the range of temperatures used. It is possibly stemmed from the nearly total exhaustion of oxygen introduced. The selectiveties of hydrogen and carbon monoxide did not largely depend on the reaction temperature. The selectivities of hydrogen and carbon monoxide were 96 and 90%, respectively. Carbon deposition observed was the smallest at $750^{\circ}C$ and the largest at $850^{\circ}C$. It is found that the proper reaction temperature is $750^{\circ}C$. The best reactant flow rate was 150 ml/min.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.212-212
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• 2000

Since the first obserbvation of carbon nanotubes, extensive researches have been done for the synthesis using arc discharge, laser vaporization, and plasma-enhanced chemical vapor deposition. Carbon nanotubes have unique physical and chemical properties and can allow nanoscale devices. Vertically aligned carbon nanotubes with high quality on a large area is particularly important to enable both fundamental studies and applications, such as flat panel displays and vacuum microelectronics. we have grown vertically aligned carbon nanotubes on a large area of Si substrates by thermal chemical vapor deposition using C2H2 gas at 750-950$^{\circ}C$. we deposited catalytic metal on Si susbstrate using thermal evaporation. The nanotubes reveal highly purified surface. The carbon nanotubes have multi-wall structure with a hollow inside and it reveals bamboo structure agreed with base growth model. Figure 1 shows SEM micrograph showing vertically aligned carbon nanotubes whih were grown at 950$^{\circ}C$ on a large area (20mm${\times}$30mm) of Si substrates. Figure 2 shows TEM analysis was performed on the carbon nanotubes grown at 950$^{\circ}C$ for 10 min. The carbon nanotubes are multi-wall structure with bamboo shape and the lack of fringes inside the nanotube indicates that the core of the structure is hollow. In our experiment, carbon nanotubes grown by the thermal CVD indicate base growth model.

• Korean Journal of Materials Research
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• v.13 no.3
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• pp.150-154
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• 2003

Amorphous carbon nitride films were deposited on Si(001) substrates by a plasma enhanced chemical vapor deposition technique (PECVD) using $CH_4$and $N_2$as reaction gases. The growth and film properties were investigated while the gas ratio and the working pressure were changed systematically. At 1 Torr working pressure, an increase in the $N_2$partial pressure results in a significant increase of the deposition rate as well as an apparent presence of C ≡N bonding, while little affecting the microstructure and amorphus nature of the films. In the case of changing the working pressure at a fixed $N_2$partial pressure of 98%, a film grown at a medium pressure of $1${\times}$10^{-2}$ Torr shows the most prominent C=N bonding nature and photoluminescent property.

• The Korean Journal of Ceramics
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• v.4 no.1
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• pp.20-24
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• 1998

Thin films of diamond-like carbon(DLC) can be successfully deposited by using a magnetron plasma chemical vapor deposition (CVD) method with an rf(13.56 MHz) plasma of $C_dH_8$. Plasma characteristics are analyzed as a function of the magnetic field. As the magnetic field increases, both electron temperature ($T_e$) and density ($n_e$)increase, but the negative dc self-bias voltage (-$V_{ab}$) decreases, irrespective of gas pressures in the range of 1~7 mTorr. High deposition rates have been obtained even at low gas pressures, which may be attributed to the increased mean free path of electrons in the magentron plasma. Effects of rf power and additive gas on the structural properties of DLC films aer also examined by using various technique namely, TED(transmissio electron diffraction) microanalysis, FTIR, and Raman spectroscopies.

• Journal of Industrial Technology
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• v.35
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• pp.89-94
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• 2015

Graphene is a carbon-based two dimensional honeycomb lattice with monoatomic thickness and has attracted much attention due to its superior mechanical, electronic, and physical properties. Here, we present a synthesis of high quality graphene on Pt substrate using a chemical vapor deposition (CVD). We optimized synthesis condition with various parameters such as synthesis temperature, time, and cooling rate. Based on the results, we concluded that graphene synthesis is driven by mainly carbon adsorption on surface rather than precipitation of carbon which is dominant in other metal substrate. In addition, Pt substrate can be repeatedly used several times with high quality graphene.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1169-1173
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• 2015

This paper presents vertical carbon nanotube (CNT) field effect transistors (FETs). For the first time, the author successfully fabricated vertical CNT-based FETs on an anodized aluminum oxide (AAO) template by using atomic layer deposition (ALD). Single walled CNTs were vertically grown and aligned with the vertical pores of an AAO template. By using ALD, a gate oxide material (Al₂O₃) and a gate metal (Au) were centrally located inside each pore, allowing the vertical CNTs grown in the pores to be individually gated. Characterizations of the gated/vertical CNTs were carried and the successful gate integration with the CNTs was confirmed.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.262-267
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• 2015

We demonstrate the growth of single-walled carbon nanotubes (SWNTs) using ethylene-based chemical vapor deposition (CVD) and ferritin-induced catalytic particles toward growth temperature reduction. We first optimized the gas composition of $H_2$ and $C_2H_4$ at 500 and 30 sccm, respectively. On a planar $SiO_2$ substrate, high density SWNTs were grown at a minimum temperature of $760^{\circ}C$. In the case of growth using nanoporous templates, many suspended SWNTs were also observed from the samples grown at $760^{\circ}C$; low values of $I_D/I_G$ in the Raman spectra were also obtained. This means that the temperature of $760^{\circ}C$ is sufficient for SWNT growth in ethylene-based CVD and that ethylene is more effective that methane for low temperature growth. Our results provide a recipe for low temperature growth of SWNT; such growth is crucial for SWNT-based applications.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1383-1386
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• 1997

Dimond-like carbon(DLC) films have been deposited by using both rf plasma-enhanced chemical vapor deposition (PECVD) and filtered cathodic vacuum arc (FCVA) deposition systems. Effects of deposition conditions, such as dc self-bias, $CH_4$ gas pressure, substrate bias, and $N_2$ partial pressure, on the structural and electrical properties of DLC films are examined. The experimental results obtained have also been discussed by considering a theoretical model for film growth.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.973-976
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• 2008

In addition to its similarity to genuine diamond film, diamond-like carbon (DLC) film has many advantages, including its wide band gap and variable refractive index. In this study, DLC films were prepared by the RF PECVD (Plasma Enhanced Chemical Vapor Deposition) method on silicon substrates using methane ($CH_4$) and hydrogen ($H_2$) gas. We examined the effects of the RF power on the electrical properties of the DLC films. The films were deposited at several RF powers ranging from 50 to 175 W in steps of 25 W. The leakage current of DLC films increased at higher deposition RF power. And the resistivities of DLC films grown at 50 W and 175 W were $5\times10^{11}$ ${\Omega}cm$ and $2.68\times10^{10}$ ${\Omega}cm$, respectively.