• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.65-70
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• 2006

Carbon nanotubes (CNT) grown by chemical vapor deposition (CVD) and plasma enhanced chemical vapor deposition (PECVD), and followed by annealing at $400{\sim}500^{\circ}C$ were investigated for gas sensing under 1.5ppm $NO_{2}$ concentration at an operating temperature of $200^{\circ}C$. The electrical resistance of CNT sensor decreased with temperature, indicating a semiconductor type. The resistance of CNT sensor decreased with $NO_{2}$ adsorption. It was found that the sensitivity of sensor was affected by humidity and decreased under microwave irradiation for 3 minutes. The CNT sensor grown by PECVD had a higher sensitivity than that of CVD.

• Journal of the Korean institute of surface engineering
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• v.52 no.6
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• pp.357-363
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• 2019

We investigated a synthesis yield and diameter distribution of single-walled carbon nanotubes (SWNTs) with respect to the growth position in a horizontal chemical vapor deposition (CVD) chamber. Thin films and line-patterned Fe films (0.1 nm thickness) were prepared onto ST-cut quartz substrates as catalyst to compare the growth behavior. The line-patterned samples showed higher growth density and parallel alignment than those of the thin film catalyst samples. In addition, line density of the aligned SWNTs at central region of the chamber was 7.7 tubes/㎛ and increased to 13.9 tubes/㎛ at rear region of the CVD chamber. We expect that the enhanced amount of thermally decomposed feedstock gas may contribute to the growth yield enhancement at the rear region. In addition, the lamina flow in the chamber also contribute to the perfect alignment of the SWNTs based on the value of gas velocity, Reynold number, and Knudsen coefficient we employed.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.98-102
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• 2005

This article describes a study of chemical vapor deposition (CVD) of copper thin films on TiN substrates using (HFAC)Cu(DMB) as a precursor. The surface morphology and conformality of the Cu films as functions of substrate temperature and the presence or absence of iodine have been investigated. The surface roughness was increased significantly along with decrement of the step coverage by increasing the deposition temperature. The highest conformal films with the lowest surface roughness were obtained using the process of copper CVD, where iodine vapor were discretely introduced into the reactor during the growth of copper.

• Korean Journal of Materials Research
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• v.12 no.11
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• pp.850-855
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• 2002

Silica powders were prepared from $SiCl_4$-$H_2$O system by chemical vapor deposition process, and investigated on size control of the products with reaction conditions. The products were amorphous and nearly spherical particles with 130nm~50nm in size. The size distribution became narrow with the increase of [$H_2$O]/[SiCl$_4$] concentration ratio. The particle size decreased with the increase of reaction temperature, [$H_2$O]/[SiCl$_4$] concentration ratio and total flow rate. The specific surface area measured by BET method was about three times larger than that of electron microscope method.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.21.1-21.1
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• 2011

Vertically aligned single-crystal ZnO nanowires have been successfully grown on c-plane sapphire substrate using chemical vapor deposition (CVD) without catalyst. According to growth temperatures, it was changed ZnO growth characteristic. We investigated the effect of substrate temperatures on the growth ZnO films or nanowires on c-plane (0001) sapphire substrates. The ZnO films were acquired at $500^{\circ}C$, whereas the ZnO nanowires were obtained at $600^{\circ}C$, $700^{\circ}C$, and $800^{\circ}C$. The growth behavior diameter and growth rate of ZnO were changed due to different temperature. As a result of analyzing in-plane residual stress by X-ray diffraction, the optimized condition of ZnO nanowires were at $600^{\circ}C$.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.277.1-277.1
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• 2016

We report on synthesis of large-area MoS2 using chemical vapor deposition (CVD). Relatively uniform MoS2 are obtained. To fabricate field-effect transistor (FET) devices, MoS2 films are transferred to another SiO2/Si substrate using polystyrene (PS) and patterned using oxygen plasma. In addition, to reduce contact resistance, synthesis of graphene used as channel. Device characteristics are presented and compared with the reported results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.131-134
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• 2001

Vertically aligned carbon nanotubes are grown on iron-deposited silicon oxide substrates by thermal chemical vapor deposition of acetylene gas at the temperature range 750∼950$^{\circ}C$. As the growth temperature increases from 750 to 950$^{\circ}C$, the growth rate increases by 4 times and the average diameter also increases from 30 nm to 130 nm while the density increases progresively with the growth temperature and a higher degree of crystalline perfection can be achieved at 950$^{\circ}C$. This result demonstrates that the growth rate, diameter, density, and crystallinity of carbon nanotubes can be controlled with the growth temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.590-590
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• 2013

Direct growth of graphene using CVD method has been done on CVD grown boron nitride substrate. From the SEM image, we have shown that the size of grain of graphene could be clearly controlled by varying the amount of injected hydrocarbon. To convince the existence of graphene on boron nitride, XPS and Raman has been checked. Both B1s and N1s peaks in XPS spectra and the Raman peak around 1,370 $cm^{-1}$ demonstrated that boron nitride did remain after high temperature treatment during the graphene growth process. And along the graphene grain boundary, the Raman fingerprint of graphene was neatly appeared.

• Environmental Engineering Research
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• v.7 no.4
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• pp.227-237
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• 2002

Chemical vapor deposition (CVD), ion beam sputtering (IBS) and sol-gel method were used to prepare TiO$_2$ thin films for degradation of hazardous organic compounds exemplified by 2-chlorophenol (2-CP). The influence of supporting materials and coating methods on the photocatalytic activity of the TiO$_2$ thin films were also studied. TiO$_2$ thin films were coated onto various supporting materials including steel cloth (SS), copper cloth, quartz glass tube (QGT), and silica gel (SG). Results indicate that SS (37 μm)- TiO$_2$ thin film prepared by IBS method improves the photodegradation of 2-CP. Among all supporting materials studied, SS(37 μm) is found to be the best support.