• Carbon letters
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• v.16 no.1
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• pp.57-61
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• 2015

Carbon aerogel is a porous carbon material possessing high porosity and high specific surface area. Nitrogen doping reduced the specific surface area and micropores, but it furnished basic sites to improve the $CO_2$ selectivity. In this work, N-doped carbon aerogels were prepared with different ratios of resorcinol/melamine by using the sol-gel method. The morphological properties were characterized by scanning electron microscopy (SEM). Nitrogen content was studied by X-ray photoelectron spectroscopy (XPS) and the specific surface area and micropore volume were analyzed by $N_2$ adsorption-desorption isotherms at 77 K. The $CO_2$ adsorption capacity was investigated by $CO_2$ adsorption-desorption isotherms at 298 K and 1 bar. Melamine containing N-doped CAs showed a high nitrogen content (5.54 wt.%). The prepared N-doped CAs exhibited a high $CO_2$ capture capacity of 118.77 mg/g (at resorcinol/melamine = 1:0.3). Therefore, we confirmed that the $CO_2$ adsorption capacity was strongly affected by the nitrogen moieties.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1448-1449
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• 2006

Pb(Zr,Ti)$O_3$ is one of the most attractive ferroelectric materials for realizing the FeRAM due to its higher remanant polarization and the ability to withstand higher coercive fields. Generally, the ferroelectric materials were patterned by a plasma etching process for high-density FeRAM. The applicable possibility of CMP process to pattern Pb(Zr,Ti)$O_3$ instead of plasma etching process was investigated in our previous study for improvement of an angled sidewall which prevents the densification of ferroelectric memory and is apt to receive the plasma damage. Our previous study showed that good removal rate with the excellent surface roughness compared to plasma etching process were obtained by CMP process for the patterning of Pb(Zr,Ti)$O_3$. The suitable selectivity to TEOS without any damage to the structural property of Pb(Zr,Ti)$O_3$ was also guaranteed. In this study, the removal mechanism of $Pb_{1.1}(Zr_{0.52}Ti_{0.48})O_3$ coated by sol-gel method was investigated. Surface analysis of polished specimens at the best and worst conditions was carried out by XPS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.348-349
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• 2006

$LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ cathode material was synthesized by a mixed hydroxide methode. The surface of the $LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ was coated with a carbon by using a sol-gel method to improve further its electrochemical properties. Electrochemical studies were performed by assembling 2032 coin cells with lithium metal as an anode. OSC (differential scanning calorimetry) data showed that exothermic reactions of charged to 4.3V vs. Li was suppressed in the carbon-coated materials. The carbon-coated $LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ showed the improved rate capability and thermal stability.

• Fibers and Polymers
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• v.5 no.2
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• pp.105-109
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• 2004

The synthesis of titanium dioxide nanofibers with 200-300nm diameter was presented. The new inorganic-organic hybrid nanofibers were prepared by sol-gel processing and electrospinning technique using a viscous solution of titanium isopropoxide (TiP)/poly(vinyl acetate) (PVAc). Pure titanium dioxide nanofibers were obtained by high temperature calcination of the inorganic-organic composite fibers. SEM, FT-IR, and WAXD techniques were employed to characterize these nanofibers. The titanium dioxide nanostructured fibers have rougher surface and smaller diameter compare with PVAc/TiP composite nanofibers. The anatase to rutile phase transformation occurred when the calcination temperature was increased from $600^{\circ}C$ to $1000^{\circ}C$.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.123-126
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• 2011

Titanium dioxide ($TiO_2$) thin films were deposited by the sol-gel method with a surfactant-assisted mechanism. Its application for dye-sensitized solar cells (DSSCs) was investigated. Brunauer-Emmett-Teller, X-ray diffraction and field emission scanning electron microscopy techniques were used to characterize the surface characteristics of thin films. Photovoltaic-current density measurements were performed to determine the photoelectrochemical properties of the thin films and the performance of DSSCs. Energy conversion efficiency of about 6.1% was achieved for cells with conductive glass under illumination with AM 1.5 (100 $mWcm^{-2}$) simulated sunlight. Investigation showed higher photo-energy conversion efficiency for mesoporous $TiO_2$ nanocrystalline films used in DSSCs relative to commercially available Degussa P25 films.

• Journal of the Korean Ceramic Society
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• v.36 no.5
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• pp.459-464
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• 1999

A carbon-containing silica glass was prepared from orgaincally modified silicate(Ormosil) by heat treatment in N2 atmosphere after the ormosil was synthesized using sol-gel method. The Ormosil was fabricated from the TEOS as the inorganic component and the PDMS as the organic component. The Ormosil changed to balck-coloured glass by carbon decomposed from the PDMS when the Ormosil was heated to 450$^{\circ}C$ 20hrs. A dense silicon oxycarbide glass with 2.08 g/cm3 was obtained by heating the Ormosil at 1050$^{\circ}C$ 10hrs. The microstructure of the carbon-containing silica glass was observed by SEM and the SiOxC4-x structure was confirmed by XPS measurement. The densification of the glass was studied by measurements of specific surface area linear shrinkage and geometric density.

• Journal of the Korean Ceramic Society
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• v.48 no.3
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• pp.211-216
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• 2011

Nickel oxide-doped ACF and $TiO_2$ composites (NiO/ACF/$TiO_2$) were prepared by a sol-gel method. The composite obtained was characterized by BET surface area measurements, X-ray diffraction, transmission electron microscopy and energy dispersive X-ray analysis. A methylene blue (MB) solution under visible light irradiation was used to determine their photocatalytic activity. Excellent photocatalytic degradation of the MB solution was observed using the $TiO_2$, Ti-ACF and NiO/ACF/$TiO_2$ composite under visible light.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.524-526
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• 2009

The effects of In and Ga contents on characteristics of InGaZnO (IGZO) films grown by a sol-gel method and their thin film transistors (TFTs) have been investigated. Excess In incorporation into IGZO enhances the field effect mobilities of the TFTs due to the increase in conducting path ways, and decreases the grain size and the surface roughness of the films because more $InO_2^-$ ions induce cubic stacking faults with IGZO. Ga incorporation into results in decrease in carrier concentration of films and off-current of TFTs since Ga ion forms stronger chemical bonds with oxygen than Zn and In ions, acting as a carrier killer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.411-414
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• 1998

In this paper, the silicon-nitride membrane structure for IR sensor was fabricated through the etching and the direct bonding. The PT layer as a IR detection layer was deposited on the membrane and its characteristics were measured. The attack of PT layer during the etching of silicon wafer as well as the thermal isolation of the IR detection layer can be solved through the method of bonding/etching of silicon wafer. Because the PT layer of c-axial orientation rained thermal polarization without polling, the more integration capability can be achieved. The surface roughness of the membrane was measured by AFM, the micro voids and the non-contacted area were inspected by IR detector, and the bonding interface was observed by SEM. The polarization characteristics and the dielectric characteristics of the PT layer were measured, too.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.815-819
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• 1998

The silicon-nirtide membrane structure for IR sensor was fabricated through the etching and the direct bonding. The PRO($PbTiO_3$ ) layer for a IR detection was coated on the membrane and its characteristics were measured. The a attack of PTO layer during the etching of silicon wafer as well as the thermal isolation of the IR detection layer were eliminated through the method of bonding/etching of silicon wafer. The surface roughness of the membrane was measured by AFM, the micro voids and the non-contacted area were inspected by the PTO layer were measured, too.