• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1190-1192
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• 1995

Poly(vinylidene fluoride)(PVDF) is one of the most studied polymers in the latest date. The interest in PVDF lies in its remarkable piezoelectric and pyroelectric properties. Also, PVDF has at least four known crystalline structures(; they are referred to as the ${\alpha},\;{\beta},\;{\gamma}\;and\;{\alpha}_p$ phase or forms II, I, III and $IV_p$). In this study, the manufactured PVDF thin film through vapor deposition method had form II(; the glass at $70^{\circ}C$). This thin film was investigated by x-ray diffraction(XRD), Fourier Transform Infrared(FT-IR) spectroscopy and Differential Thermal Analysis(DTA). XRD and FT-IR indicate crystallization forms from the glass at $70^{\circ}C$ into form II.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1080-1086
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• 2007

The aim of this paper is to establish the optimum fabrication condition of specimens, using the Vapor Deposition Polymerization Method(VDPM), which is one of modesto prepare functional organic thin films using a dry process, and to develop a thin film type humidity sensor which has good humidity sensitive characteristics. The inner part of the film became denser and roughness of the film surface eased as curing temperature increased so that thickness of the film could be made uniform. This also shows the appropriate curing temperature was $250^{\circ}C$. The basic structure of the humidity sensor is a parallel capacitor which consists of three layers of Aluminum/Polyimide/Aluminum. The result of SEM and AFM measurement shows that the thickness of PI thin films decreased and the refraction increased as curing temperature increased, which indicates that a capacitance-type humidity sensor utilizing polyimide thin film is fabricated on a glass substrate. The characteristics of fabricated samples were measured under various conditions, and the samples had linear characteristics in the range of 20-80 %RH, independent of temperature change, and low hysteresis characteristic.

• Journal of Photoscience
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• v.7 no.1
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• pp.27-30
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• 2000

The Photoluminescence (PL) measurement results of a very good quality GaN sample grown by metalorganic chemical vapor deposition (MOCVD) are reported. The temperature dependences of peak position, emission intensity, and the full width at half maximum (FWHM) of free-exciton (FX) A and B are presented. Our results show the fast thermal quenching of FX transition intensities and predominantly acoustic phonon scattering of emission line broadening. The transition-energy-shift following the Varshni's empirical equation, and by using it to fit the data, E$\_$A1/(T) = 3.4861 eV -6.046 $\times$ 10$\^$-4/T$^2$ (620.3+ T) eV, E$\_$B1/(T) = 3.4928 eV -4.777 $\times$ 10$\^$-4/T$^2$ / (408.2+ T) eV and E$\_$A2/ = 3.4991 eV -4.426 $\times$ 10$\^$-4/ T$^2$ / (430.6+ T) eV for A(n=1), B(n=1), and A(n=2) are obtained respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.293-293
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• 2010

Carbon nanotubes (CNTs) have attracted considerable attention as possible routes to device miniaturization due to their excellent mechanical, thermal, and electronic properties. These properties show great potential for devices such as field emission displays, CNT based transistors, and bio-sensors. The metals such as nickel, cobalt, gold, iron, platinum, and palladium are used as the catalysts for the CNT growth. In this study, diamond-like carbon (DLC) was used for CNT growth as a nonmetallic catalyst layer. DLC films were deposited by a radio frequency (RF) plasma-enhanced chemical vapor deposition (RF-PECVD) method with a mixture of methane and hydrogen gases. CNTs were synthesized by a hot filament plasma-enhanced chemical vapor deposition (HF-PECVD) method with ammonia (NH3) as a pretreatment gas and acetylene (C2H2) as a carbon source gas. The grown CNTs and the pretreated DLC filmswere observed using field emission scanning electron microscopy (FE-SEM) measurement, and the structure of the grown CNTs was analyzed by high resolution transmission scanning electron microscopy (HR-TEM). Also, using energy dispersive spectroscopy (EDS) measurement, we confirmed that only the carbon component remained on the substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.247-250
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• 2001

We studied optical properties of SiON thin-film in the applications of optical waveguide. SiON thin-film was grown in $300^{\circ}C$ by PECVD(plasma enhanced chemical vapor deposition) system. The change of SiON thin-film composition and refractive Index was studied as a function of varying $NH_3$ gas flow rate. As $NH_3$ gas flow rate was increased, Quantity of N and refractive index were increased at the same time. By the results, we could form the SiON thin-film to use of a waveguide with refractive index of 1.6. We analyzed the conditions of the thin-film with FTIR(fourier transform infrared) and OES (optical emission spectroscopy). N-H bonding($3390cm^{-1}$ ) can be removed by thermal annealing. And we could observe the SiH bonding state and quantity by OES analysis in $SiH_4$

• Journal of the Korean Graphic Arts Communication Society
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• v.24 no.2
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• pp.49-59
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• 2006

In this paper, a transparent film exposed the effect of heat cut-off, reveal as means of the prevention to wrong operation of parts of display and forgery of the credit card, also it will intercept rising of the temperature in interior of a room and car by diminish the influx of near-infrared ray wavelength of solar energy come from the window. As in the past a film which absorb a wavelength of $800{\sim}2500nm$ in near-infrared ray, manufactured in physical vapor deposition(PVD), chemical vapor deposition(CVD) to using ATO, ITO of inorganic materials or sputtering method. but it has lots of problem in manufacture. On the other hand, recently a paper said it easily form a transparent film to using organic dye. This paper show synthesis of many derivatives used in Ni-complex and then it investigate to optical property and durability of flim by make the transparent film.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1110-1114
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• 2001

We report the mechanochemical effect of an Fe(NO$_3$)$_3$$.$9H$_2$O-Al(OH)$_3$sample as catalytic precursor mixed-ground by mixer mill on the growth of carbon nanotubes using thermal chemical vapor deposition method. From and TEM observations, carbon products grown on a ground catalyst were more uniform than those grown on an unground catalyst and most of them were identified as carbon nanobubes. Also, it was observed that field emission properties of products on ground catalyst were superior to those of unground catalyst.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1628-1630
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• 2000

Vertically aligned multiwalled carbon nanotubes are grown on silicon oxide substrate at 950$^{\circ}C$ by thermal chemical vapor deposition using $C_{2}H_2$. Three catalytic metals such as iron(Fe), cobalt (Co), and nickel(Ni) are used as catalyst, we found that the growth rate of carbon nanotubes for three catalyst particles are in an order of Fe > Ni > Co. All carbon nanotubes are revealed to have bamboo structure with no encapsulated catalytic particles, the diameter of carbon nanotubes depend on the catalyst, the tip and the compartment sheets of bamboo structure also depend on the shape of catalytic particles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.247-250
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• 2001

We studied optical properties of SiON thin-film in the applications of optical waveguide. SiON thin-film was grown in 300$^{\circ}C$ by PECVD(plasma enhanced chemical vapor deposition) system. The change of SiON thin-film composition and refractive Index was studied as a function of varying NH$_3$ gas flow rate. As NH$_3$ gas flow rate was increased, Quantity of N and refractive index were increased at the same time. By the results, we could form the SiON thin-film to use of a waveguide with refractive index of 1.6. We analyzed the conditions of the thin-film with FTIR(fourier transform infrared) and OES(optical emission spectroscopy). N-H bonding(3390cm$\^$-1/) can be removed by thermal annealing. And we could observe the SiH bonding state and quantity by OES analysis in SiH$_4$

• Journal of Surface Science and Engineering
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• v.50 no.6
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• pp.516-522
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• 2017

We report the growth of carbon nanotubes (CNT) on Invar-42 plates using coal tar pitch (CTP) by chemical vapor deposition (CVD) method. The solid phase CTP is used as an inexpensive carbon source since it produces a bunch of hydrocarbon gases such as $CH_4$ and other $C_xH_v$ by thermal decomposition over $450^{\circ}C$. The Invar-42 is a representative Ni-based ferrous alloy and can be used repetitively as a substrate for CNT growth because Ni and Fe are used as very active catalytic elements. We changed mixing ratio of carrier gases, argon and hydrogen, and temperature of growth region. It was found that the optimum gas ratio and temperature for high quality CNT growth are $Ar:H_2=400:400$ sccm and $1000^{\circ}C$, respectively. In addition, the carbon nanoball (CNB) was also obtained by just changing the mixing ratio to $Ar:H_2=100:600$ sccm. Finally, CTP can be employed as a versatile carbon source to produce various carbon-based nanomaterials, such as CNT and CNB.