• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.210-210
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• 2011

Ultrasmall electodes are of great importance for basic electrochemical study and applications. We fabricated single crystal (111) Au nanowire (NW) by growth mechanism on substrate without any catalyst. Consequently, these high aspect NW combined with tungsten microwire and the electrodes having NW tip on their end were obtained. These single crystal Au (111) NWs were characterized by electron microscope and electrochemical analysis. We show that precise electrochemical measurement could be possible on these NW electrode by obtaining underpotential deposition (UPD) and ferricyanide CV profiles on the electrode. The immersed depth of electrode into solution was controlled in micrometer scale by piezo-driven manipulator.

• Journal of Information Display
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• v.12 no.2
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• pp.109-113
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• 2011

This paper summarizes the recent fabrication and characterizations of flexible high-speed radio frequency (RF) transistors, PIN-diode single-pole single-throw switches, as well as flexible inductors and capacitors, based on single-crystalline Si nanomembranes transferred on polyethylene terephthalate substrates. Flexible thin-film transistors (TFTs) on plastic substrates have reached RF operation speed with a record cut-off/maximum oscillation frequency ($f_T/f_{max}$) values of 3.8/12 GHz. PIN diode switches exhibit excellent ON/OFF behaviors at high RF frequencies. Flexible inductors and capacitors compatible with high-speed TFT fabrication show resonance frequencies ($f_{res}$) up to 9.1 and 13.5 GHz, respectively. Robust mechanical characteristics were also demonstrated with these high-frequency passives components.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.269-274
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• 1997

Silicon carbide(SiC) epilayers were grown by a thermal CVD(chemical vapor deposition) process, and their crystalline properties were investigated. Especially, the growth conditions of 6H-Sic homoepitaxial layers were obtained using a SiC-uncoated graphite susceptor that utilized Mo-plates. In order to investigate the crystallinity of grown layers, Nomarski photograph, transmittance, XRD, Raman, PL and TEM measurements were used. The best quality of 6H-SiC epilayers was obtained in conditions of growth temperature 1500$^{\circ}C$ and C/Si ratio 2.0.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.115-115
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• 2009

Epitaxial ZnO film was grown on Si(111) substrate with oxidazed CrN buffer by plasma-assisted molecular beam epitaxy (PAMBE). The growth and structural properties are investigated. The single crystalline growth was revealed by in-situ RHEED analysis. Crystalline quality of ZnO film grown on oxidized CrN buffer was investigated by the X-ray rocking curves. The FWHMs of (0002) XRCs was $1.379^{\circ}$. This value was smaller than the ZnO film grown directly on (111) Si substrate.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.71-74
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• 1998

$Er^{3+}$ doped $NdF_{3}$ single crystalline thin films with smooth, microcrack-free, and high-crystalline quality were grown on $CaF_{2}(111)$ substrate at $500^{\circ}C$by molecular beem epitaxy(MBE). The relation-ship between subcell and supercell showing the reconstructed $3^{1/2} \times 3^{1/2}$ structure was studied by reflection high-energy electron diffraction(RHEED) investigation. The film surface and the growth mode were examined in studied by RHEED patterns and atomic force microscope(AFM) images ex situ. The crystallinity of film and the lattice mismatch between $NdF_{3}Er}^{3+}(0002)$ film and $CaF_{2}(111)$ substrate depending in the $Er^{3+}$ concentration were investigated by X-ray rocking curve analysis.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.3
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• pp.120-125
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• 2002

Si-wafers for solar cells were cast in a size of $50{\times}46{\times}0.5{\textrm}{mm}^3$ by vacuum casting method. The graphite mold coated by BN powder, which was to prevent the reaction of carbon with the molten silicon, was used. Without coating, the wetting and reaction of Si melt to graphite mold was very severe. In the case of BN coating, SiC was formed in the shape of tiny islands at the surface of Si wafer by the reaction between Si-melt and carbon of the graphite mold on the high temperature. The grain size was about 1 mm. The efficiency of Si solar cell was lower than that of Si solar cell fabricated on commercial single and poly crystalline Si wafer. The reason of low efficiency was discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.3
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• pp.257-262
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• 2001

Single crystalline films of La doped YIG(yttrium iron garnet) were grown by the liquid phase epitaxy. The lattice constants of films obtained by DCD(double crystalline diffractometer) measurement increased with increasing La contents in films. In particular, lattice constants of films grown wiht Y/La=20 solution were nearly same as those of GGG (gadolinium gallium garnet) substrate. The saturation magnetization measured with VSM (vibrating sample magnetometer) was about 1750Gauss which is the same as that of pure YIG irrespective of La contents in films. FMR(ferromagnetic resonance) linewidth of La doped YIG was smaller than that of pure YIG. Since appropriate La doping decreases the lattice mismatch between film and substrate, the FMR linewidth was Y/La=20 in this experiment.

• Proceedings of the Korean Fiber Society Conference
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• 1987.06b
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• pp.12-12
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• 1987

To improve the fibrillation phenomenon and processibili to of poly(p-phenyleneterephthalamide) (PPD-T) , a P/E copolyamide was prepared by introducing 4,4'-ethylene dianiline (EDA) into rigid chain backbone. The effects of semi-flexible segment on the liquid crystalline properties were investigated. The EDA, used as a comonomer, was prepared by catalylitic reduction of p,p'-dinitrophenyl , obtained by oxidative coupling of p,p'-dinitrotoluene. Various high molecular weight PIE copolyamides were prepared by low temperature solution polycondensation of terephthaloyl chloride (TPC) with various mixtures of p-phenylene diamine (PPD) and EOA. The PfE copolyamides were completely dissolved in 100% svlfuric acid, and the phase transition of P/E copolyamide-sulfuric acid systems was examined in teams of concentration and temperature. Over the chemical compositions, PIE=911, 812, and 713, solutions of anisotropic single phase were acquired. In particular, the two mixing ratios, 911 and 812, gave a good anisotropic spinning dope.

• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.300-303
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• 2000

The generation of the intermodulation noises in microwave isolators has been studied in relation to the characteristics of YIG ferrites designed for this application. We have investigated the influences of porosity and crystalline anisotropy related to the magnetic loss, which causes the generation of intermodulation signals. The power dependence of the intermodulation power level is stressed as the crystalline anisotropy decreases. These results are consistent with the nonlinear effects of a single normal mode before the excitation of the spin-waves. It also appears that this power level is proportional to the magnitude of dc bias magnetic field.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.265-268
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• 2001

Robust control for DC motor is needed according to the highest precision of industrial automation. It is a quite quality concerning to control temperature of single crystalline growth as it does when you get most of heat treating products. It is also Important factor to control temperature when you make the A1203(sing1e crystalline) used to artificial Jewels, glass of watches, heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while you are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system f3r the gas mixture to improve the quality of products.