• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.148-151
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• 2000

$Mg_{2-2x}Ti_xO_2$ films were prepared by e-beam evaporation method to be used as possible substitutes for the conventional MgO protective layer. The oxygen content in the films and in turn, the ratio of metal to oxygen gradually increased with increasing the $TiO_2$ content in the starting materials. The pure MgO films exhibited the crystallinity with strong (111) orientation. The $Mg_{2-2x}Ti_xO_2$ films, however, had the crystallinity with (311) preferred orientation. When the $[TiO_2/(MgO+TiO_2)]$ ratios of 0.1 and 0.15 were used, the deposited films exhibited the secondary electron emission yields improved by 50% compared to that of the conventional MgO protective layer, which resulted in reduction in discharge voltage by 12%.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.354-354
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• 2012

In this study, we report the vertically aligned ZnO nanowires by using different type of Ga-doped ZnO (GZO) thin films as seed layers to investigate how the underlying GZO film micro structure affects the distribution of ZnO nanowires. Arrays of highly ordered ZnO nanowires have been synthesized on GZO thin film seed layer prepared on p-Si substrates ($7-13{\Omega}cm$) with utilize of a pulsed laser deposition (PLD). With the vapor-liquid-solid (VLS) growth process, the ZnO nanowire synthesis carries out no metal catalyst and is cost-effective; furthermore, The GZO seed layer facilitates the uniform growth of well-aligned ZnO nanowires. The influence of the growth temperature and various thickness of GZO seed layer have been analyzed. Crystallinity of grown seed layer was studied by X-Ray diffraction (XRD); diameter and morphology of ZnO nanowires on seed layer were investigated by field emission scanning electron microscopy (FE-SEM). Our results suggest that the GZO seed layer with high c-axis orientation, good crystallinity, and less lattice mismatch is key parameters to optimize the growth of well-aligned ZnO nanowire arrays.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.353-355
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• 2004

YBaCuO thick films were fabricated by plasma enhanced chemical vapor deposition, and the crystallinity and the superconducting properties were investigated. The growth temperature to obtain the thick films was decreased by around $150^{\circ}C$ due to plasma enhancement. The zero resistivity temperatures for films grown at $590^{\circ}C$ and $620^{\circ}C$ were 55 and 80 K, resistively.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1491-1494
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• 2014

High-crystallinity poly(3-hexylthiophene) (P3HT) thin films were prepared by aging the precursor solutions, prepared using a good solvent, chloroform, at low temperatures prior to spin-casting. Lower solution temperatures significantly improved the molecular ordering in the spin-cast P3HT films and, therefore, the electrical properties of field-effect transistors prepared using these films. Solution cooling enhanced the electrical properties by shifting the P3HT configuration equilibrium away from random coils and toward more ordered aggregates. At room temperature, the P3HT molecules were completely solvated in chloroform and adopted a random coil conformation. Upon cooling, however, the chloroform poorly solvated the P3HT molecules, favoring the formation of ordered P3HT aggregates, which then yielded more highly crystalline molecular ordering in the P3HT thin films produced from the solution.

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.294-302
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• 1998

$Pb_{1+x}$($Fe_{0.5}$$Nb_{0.5}$)$O_3$ films have been synthesized on Pt/Ti/$SiO_2$/Si substrates using rfmagnetron sputtering Concentration of Fe and Nb in the deposited films was adjusted to near stoichiometry through the control of target composition, Films deposited with adjusted to near stoichiometry showed better electrical properties such as dielectic and leakage characteristics. Crystallinity and dielectric constant increased with increasing excess PbO upto 9 mol% This study also showed that dielectric constant and leakage current characteristics improved by optimum content of $O_2$ flow during deposition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.27-27
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• 2008

The different concentration Indium doped ZnO:Al films were grown on glass substrates (Corning 1737) at $200^{\circ}C$ by pulsed laser deposition. The indium doping in AZO films shows the critical effect on the crystallinity, resistivity, and optical properties of the films. The AZO films doped with 0.3 atom % indium content exhibit the highest crystallinity, the lowest resistivity of $4.5\times10^{-4}\Omega$-cm, and the maximum transmittance of 93%. The resistivity of the indium doped-AZO films is strongly related with the crystallinity of the films. The carrier concentration in the indium doped-AZO films linearly increases with increasing indium concentration. The mobility of the AZO films with increasing indium concentration was reduced with an increase in carrier concentration and the decrease in mobility was attributed to the ionized impurity scattering mechanism. In an optical transmittance, the shift of the optical absorption edge to shorter wavelength strongly depends on the electronic carrier concentration in the films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.276-276
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• 2008

Transparent and conducting indium tin oxide (ITO) and ITO/Nickel/ITO(INI) multilayered films were prepared on glass substrates by a magnetron sputtering without intentional substrate heating. The RF(13.56MHz) and DC power were applied to ITO and Nickel target, respectively. The thickness of ITO, Ni and ITO films were kept constantly at 50, 5 and 45 nm. In order to consider the effect of post deposition vacuum annealing in vacuum on the physical and optoeletrical properties of INI films, optical transmittance, electrical resistivity, crystallinity of the films were analyzed. From the observed result, it may conclude that the optoelectrical properties of the INI films were dependent on the post deposition annealing. For the INI films annealed at $300^{\circ}C$, the films have a polycrystalline structure with (110), (200), (210), (211) and (300). The resistivity of the films were $4.0\times10^{-4}{\Omega}cm$ at room temperature. As the annealing($300^{\circ}C$), resistivity decreased to $2.8\times10^{-4}{\Omega}cm$. And also the optical transmittance decreased from 79 to 70 % at 550nm.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.850-852
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• 1998

SiC thin film have been prepared by ICP-CVD for low temperature deposition and large area deposition. The structural properties of deposited SiC films are characterized by employing SEM, FT-IR, XRD, XPS and Raman Spectroscopy. From the experimetal results, good crystallinity has been achieved in $1000^{\circ}C$ grown SiC film which have carbonization step at $1100^{\circ}C$ for substrate bias of 30V.

• Polymer(Korea)
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• v.39 no.1
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• pp.114-121
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• 2015

Mutli-walled carbon nanotubes (MWCNTs) were surface-modified by a hydrofluoric acid solution to remove impurities and improve interfacial bonding and dispersion of nanotubes in an epoxy matrix. The crystallinity on the surface of treated MWCNTs was investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The mechanical properties were characterized by tensile test, and the enhancement of mechanical properties of the modified MWCNTs/epoxy composites was indicated by a 33% increase in tensile strength. The electromagnetic interference shielding effectiveness (EMI-SE) of modified MWCNTs/epoxy composites was improved with an increase in concentration of hydrofluoric solution, and EMI-SE showed the maximum increase with 25% HF. However, mechanical and EMI-SE properties didn't show further increase with over 50% HF concentration because the properties of MWCNTs were influenced by degradation of crystallinity and intrinsic properties of MWCNTs. The mechanical and electrical property enhancements of the polymer composites are attributed to the modification of MWCNTs which improve crystallinity of MWCNTs and dispersion in the epoxy resin.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.361-361
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• 2012

PZT (Pb(Zr,Ti)O3) thin films have been used widely in the MEMS application, due to their inherent ferroelectric and piezoelectric properties. Such ferroelectricity induces much higher dielectric constants compared to those of the nonperovskite materials. In this work, the PZT thin films were deposited onto Indium-Tin-oxide (ITO) substrates through the spin-coating of PZT sols. The deposited PZT thin films were characterized in terms of the electrical and optical properties with special emphases on conductivity and optical constants. The detailed analysis techniques incorporate the dc-based current-voltage characteristics for the electrical properties, spectroscopic ellipsometry for optical characterization, atomic force microscopy for surface morphology, X-ray Photoelectron Spectroscopy for chemical bonding, Energy-dispersive X-ray Spectrometry for chemical analyses and X-ray diffraction for crystallinity. The ferroelectric phenomena were confirmed using capacitance-voltage measurements. The integrated physical/chemical features are attempted towards energy-oriented applications applicable to next-generation high-efficiency power generation systems.