• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.422-422
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• 2009

Photocurable inorganic-organic hybrid materials were prepared from colloidal-silica nanoparticles synthesized through the solgel process and using acryl resin. The synthesized colloidal-silica nanoparticles had uniform diameters of around 20 nm, and they were organically modified, using methyl and methacryl functional silanes, for efficient hybridization with acryl resin. The organically modified and stabilized colloidal-silica nanoparticles could be homogeneously hybridized with aeryl resin without phase separation. The successfully fabricated hybrid materials exhibit efficient photocurability and simple film formation due to the photopolymerization of the organically modified colloidal-silica nanoparticles and acryl resin upon UV exposure. The fabricated hybrid films exhibit an excellent optical transmission of above 90% in the visible region as well as an enhanced surface smoothness of around 1 nm RMS roughness. In addition, the hybrid films exhibit improved thermal and mechanical characteristics, much better than those of acryl resin. More importantly, these photocurable hybrid materials fabricated through the synergistic combination of colloidal-silica nanoparticles with acryl resin are candidates for optical and electrical applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.13-13
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• 2009

We have investigated the fabrication and properties of bendable PZT film formed on plastic substrates for the application in flexible memory. These devices used the PZT active layer formed on $SiO_2/Si$ wafer by sol-gel method with optimized device layouts and Pt electrodes. After etching Pt/PZT/Pt layers, patterned by photolithography process. these layers were transferred on PET plastic substrate using elastomeric stamp. The level of performance that can be achieved approaches that of traditional PZT. devices on rigid bulk wafers.

• Korean Journal of Materials Research
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• v.19 no.9
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• pp.481-487
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• 2009

The photocatalysts of Fe-ACF/$TiO_2$ compositeswere prepared by the sol-gel method and characterized by BET, XRD, SEM, and EDX. It showed that the BET surface area was related to adsorption capacity for each composite. The SEM results showed that ferric compound and titanium dioxide were distributed on the surfaces of ACF. The XRD results showed that Fe-ACF/$TiO_2$ composite only contained an anatase structure with a Fe mediated compound. EDX results showed the presence of C, O, and Ti with Fe peaks in Fe-ACF/$TiO_2$ composites. From the photocataytic degradation effect, $TiO_2$ on activated carbon fiber surface modified with Fe (Fe-ACF/$TiO_2$) could work in the photo-Fenton process. It was revealed that the photo-Fenton reaction gives considerable photocatalytic ability for the decomposition of methylene blue (MB) compared to non-treated ACF/$TiO_2$, and the photo-Fenton reaction was improved by the addition of $H_2O_2$. It was proved that the decomposition of MB under UV (365 nm) irradiation in the presence of $H_2O_2$ predominantly accelerated the oxidation of $Fe^{2+}$ to $Fe^{3+}$ and produced a high concentration of OH radicals.

• Journal of the Korean Ceramic Society
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• v.42 no.6 s.277
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• pp.384-390
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• 2005

[ ${\alpha}-Al_2O_3$ ] precursor was synthesised by sol-gel method using aluminum sulfate, sodium sulfate and sodium carbonate as law materials. The flaky ${\alpha}-Al_2O_3$ crystals were prepared by heating using precursor about $1,050^{\circ}C$. In this study, the effect of some transition-metal sulfate ($FeSO_4,\;SnSO_4,\;ZnSO_4$) addition have been investigated. When iron sulfate was added, it could see that act on impurities in crystal growth process. In case of tin sulfate, distribution of Platelets was very broad. When flaky ${\alpha}-Al_2O_3$ crystals were prepared zinc sulfate addition, thickness, size, and distribution of platelets was suited to industrial application. The average diameter of flaky ${\alpha}-Al_2O_3$ crystals was about 20 $\mu$m, and its thickness was about 0.3 $\mu$m. Increasing addition of zinc sulfate, thickness of ${\alpha}-Al_2O_3$ platelet was decreased.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.13-16
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• 2003

Adhesion of $SrZrO_3$ resistive oxide barrier on Ag sheathed Bi(2223) tapes prepared by the sol-gel and dip-coating method was evaluated with an aid of Taguchi method and Lie($2^1{\times}3^7$) orthogonal arrays to determine the optimal process combination of levels of factors that best satisfy the bigger is better quality characteristic (QC=B). For analyses of results statistical calculations such as average and analysis of variance (ANOVA) were employed to analyze the results for improving the performance qualities of the dip-coated $SrZrO_3$ film. Experimentally, the performance of the films was evaluated in terms of bond strength by varying Sr/Zr moi ratio (A), amount of organic vehicle additives (B), drying temperature (C) and time (D), heat treatment temperature (E) and time (F), respectively. The optimal combination of levels of factors was determined to be $A_3B_2C_3D_2E_1F_3$ having a 90% confidence level.

• Analytical Science and Technology
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• v.7 no.1
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• pp.17-23
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• 1994

Through sol-gel process, inorganic/organic composite as a dye host was made. It was observed that this composite has about 90% of trnasmittance by UV/VIS spectrophotometer. The transmittance is the most important requirement to decide whether the composite could apply or not as the dye host. The transmittance was increased with decreasing HCl as a catalyst, aging time, and amount of PDMS. Also, fluorescent and transmittant charateristics of Rhodamine 6G Perchlorate that was doped into ORMOSIL were measured. The fluorescent intensity was increased and the trnasmittance was decreased with rising gelling temperature.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.174-174
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• 2003

Highly (111)-oriented PZT [Pb(Zrl-xTix)O3] thin films in the Zr-rich rhombohedral phase-field were successfully fabricated on Pt(111)/Ti/SiO2/Si substrates by combining PLD method with sol-gel process. These highly (111)-oriented films can be used as model systems for polarized Raman scattering study of PZT in the rhombohedral-Phase field because the (111)-direction is the principal off-center axis of the rhombohedral ferroelectricity. For this purpose, we have fabricated PZT films employing two distinctive compositions : one with Zr/Ti = 90/10 (abbreviated as PZT90/10) and the other with Zr/Ti= 60/40 (PZT60/40). The PZT90/10 film belongs to the octahedrally distorted FR(LT) phase with a cell-doubled structure, whereas the PZT60/40 is in the high-temperature FR(HT) phase-field at room temperature. To clearly separate E(TO) phonon modes from Al(TO) modes of the (111)-oriented rhombohedral film, we have suitably devised Z(X,Y)Z and Z(X,X)Z backscattering geometries for E(TO) and Al (TO), respectively. The polarized scattering experiment demonstrated that both types of (111)-oriented rhombohedral films closely followed the Raman selection rule.

• Journal of Sensor Science and Technology
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• v.23 no.5
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• pp.295-298
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• 2014

A novel approach to fabricating high-performance glucose sensors is reported, which is based on the process of self-assembled monolayers (SAMs). In this study, we have particularly used ${\alpha}$-lipoic acid (LA) SAMs for the glucose sensors. To our best knowledge, this study is the first one to use LA as SAMs for this purpose. N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were deliberately attached at the same time on the LA SAM. Then, glucose oxidase ($GO_X$) and horseradish peroxidase (HRP) were sequentially immobilized. Thus, the HRP/$GO_X$/NHS-EDC/LA-SAM/Au/Cr/glass working electrode was developed. The glucose-sensing capability of the fabricated sensor was systematically measured by the use of cyclic voltammetry in the range of 1-30 mM glucose in phosphate-buffered saline. The result showed a good sensitivity, that is, as high as $27.5{\mu}A/(mM{\cdot}cm^2)$. This result conspicuously demonstrates that LA can be one of promising substances for use as SAMs for accurately monitoring trace levels of glucose concentration in human blood.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1388-1390
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• 2007

This paper investigates how various concentrations of lithium ion influence on crystallization of MgO in thin films formed by spin coating and an the discharge characteristic in a flat fluorescent lamp structure. The XRD results indicate $Li^+$ ion enhances the growth of MgO crystal in a spin coated thin film. The discharge property with the $Li^+$ ion doped MgO films show the lithium ion in MgO film clearly reduce the initial discharge voltages of test devices. Interestingly, the test panels with various doped MgO film have somewhat higher static memory margin of than that of pure-MgO owing probably to the pore structure of spin coated MgO films. The CL spectra, which confirm that the doping creates defects energy levels in the band gap of MgO, show the $F^+$ center is the main defects in doped MgO films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.176-180
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• 2006

[ $(Na_{0.5}Bi_{0.5})TiO_3$ ][NBT] thin films were prepared on a highly (100) oriented $LaNiO_3[LNO]$ by sol-gel process. X-ray diffraction patterns of the NBT films annealed above $600^{\circ}C$ for 5 minutes have confirmed a highly (100) oriented growth and pseudocubic structure (a=3.884${\AA}$). The (l00) orientation factor increased from 90 to $99\%$ with increasing soaking time from 5 to 60 minutes at $600^{\circ}C$. The NBT films ($600^{\circ}C$/5 min,) have a flat and dense microstructure with large columnar grains, and their grain size are about 44 nm. The Au/NBT/LNO/Si hetero structure sample show a ferroelectric properties.