• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.510-516
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• 1993

$PbTiO_3$ thin films have been formed by rapid thermal annealing(RTA) of $TiO_2$/Pb/$TiO_2$ multilayer films deposited on Si wafers by RF sputtering. Based on the optimal depositon conditions of TiO2 and Pb, $TiO_2$/Pb/$TiO_2$ three layers were deposited for 900$\AA$ each. These films were subjected to RTA process at the temperatures ranging from $400^{\circ}C$ to $900^{\circ}C$ for 30 seconds in air, and were analyzed by X-ray diffraction and transmission electron microscopy to investigate the phases and the microstructures. As a result, perovskite $PbTiO_3$ phases was obtained above $500^{\circ}C$ with the trace of unreacted $TiO_2$. RBS analysis revealed the anisotropic behavior of diffusion that the diffusivity of Pb to the bottom $TiO_2$ layer was faster than that of Pb to the top $TiO_2$ layer. The amorphous Pb-silicate was formed between film and Si substrate due to the diffusion of Pb, but Pb-silicate existed locally at the interface and the amount of that phase was very small. Therefore the effect of bottom $TiO_2$ layer as a diffusion barrier was confirmed. $PbTiO_3$ films formed by current technique showed a relative dielectric constant of 60, and the maximum breakdown field reached 170kV/cm.

• Journal of the Korean Ceramic Society
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• v.35 no.11
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• pp.1130-1140
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• 1998

Thin films of $Bi_4Ti_3O_{12}\;nBaTiO_3(n=1&2)$ were prepared using sols erived Ba-Bi-Ti complex alkoxides. The sols were spin-cast onto $Pt/Ti/SiO_2/Si$ substrates and followed by pyrolysis for 1 hr at $620^{\circ}C,\;700^{\circ}C\;and\;750^{\circ}C$ In the thin films a pyrochlore phase seemed to be formed at a lower temperature and then tran-formed to the layered perovskite phase as the heating temperature increased. In the thin films pyrolyzed at formed to the layered perovskte phase as the heating temperature increased. In the films pyrolyzed at $750^{\circ}C$ the amount of $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ reached to 94% while $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ was 77% in composition. This result shows that the formation of the layered pervoskite phase becomes difficult as the amount of complexing $BaTiO_3$ increases. The microstructures and the electrical properties of the thin films were gen-erally improved with the incease of the heating temperature. However the presence of the pyrochlore phase could not be removed effectively. Our study showed that the electrical properties of $Bi_4Ti_3O_{12}{\cdot}BaTiO_3$ were pronouncedly improved with complexing with BaTiO3 when compared to those of $Bi_4Ti_3O_{12}$ while the presence of the pyrochlore phase was detrimental to the those of $Bi_4Ti_3O_{12}{\cdot}2BaTiO_3$.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.79-81
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• 2004

$TiO_2-SnO_2$ thin films are fabricated using sol-gel method. The thickness of thin films increase about $0.03{\sim}0.04{\mu}m$ every a dipping. The permittivity and dissipation factor of $TiO_2-SnO_2$ thin films decrease with increasing frequency. Thin films show semiconductive characteristics above $400^{\circ}C$.

• Korean Journal of Materials Research
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• v.24 no.4
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• pp.207-213
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• 2014

Flexible $BaTiO_3$ films as dielectric materials for high energy density capacitors were deposited on polyethylene terephthalate (PET) substrates by r.f. magnetron sputtering. The growth behavior, microstructure and electrical properties of the flexible $BaTiO_3$ films were dependent on the sputtering pressure during sputtering. The RMS roughness and crystallite size of the $BaTiO_3$ increased with increasing sputtering pressure. All $BaTiO_3$ films had an amorphous structure, regardless of the sputtering pressures, due to the low PET substrate temperature. The composition of films showed an atomic ratio (Ba:Ti:O) of 0.9:1.1:3. The electrical properties of the $BaTiO_3$ films were affected by the microstructure and roughness. The $BaTiO_3$ films prepared at 100 mTorr exhibited a dielectric constant of ~80 at 1 kHz and a leakage current of $10^{-8}A$ at 400 kV/cm. Also, films showed polarization of $8{\mu}C/cm^2$ at 100 kV/cm and remnant polarization ($P_r$) of $2{\mu}C/cm^2$. This suggests that sputter deposited flexible $BaTiO_3$ films are a promising dielectric that can be used in high energy density capacitors owing to their high dielectric constant, low leakage current and stable preparation by sputtering.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.9-17
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• 1994

Optical properties of $TiO_2$ thin films prepared by ion-beam assisted deposition(1BAD) were investigated. The result shows that the refractive index of IBAD TiOL thin films measured by an envelope method is closer to that of the corresponding bulk than that of conventionally deposited $TiO_2$ thin films and the packing density of IBAD $TiO_2$ thin films measured by a vacuum-to-air spectral shift of films increases drastically. The vacuum-to-air spectral shift of an IBAD $(TiO_2/SiO_2)$ multilayer interference filter was negligible as compared to that of a conventional interference filter and so the IBAD filter is denser and more stable optically than the conventional filter. Also it is observed that the IBAD and conventional $TiO_2$ thin films are stoichiometric and amorphous.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.383-390
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• 2002

To investigate behaviors of Ti and O elements and microstructures of anodic titanium oxide films, the films were prepared by anodizing pure titanium in $H_2$S $O_4$, $H_3$P $O_4$, and $H_2O$$_2$ mixed solution at 180V. The microstructures and chemical states of the elements were analyzed using SEM, X-ray mapping, AFM, XRD, XPS (depth profile). The films formed on a titanium substrate showed porous layers which were composed of pore and wall, And with increasing anodizing time a hexagonal shape of cell structures were dominant and solace roughness increased. From the XRD result the structure of the Ti $O_2$ layer was anatase type of crystal on the whole. In the XPS spectra it was found that Ti and O were chemically binded in forms of Ti $O_2$, TiOH, $Ti_2$ $O_3$ at Ti 2p, and Ti $O_2$, $Ti_2$ $O_3$, $P_2$ $O_{5}$, S $O_4^{2-}$ at O ls respectively. Concentration of Ti $O_2$ decreased as the depth increased from the surface of the oxide film towards the substrate, but to the contrary concentrations of TiOH and $Ti_2$ $O_3$ increased.d.

• Korean Journal of Optics and Photonics
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• v.16 no.2
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• pp.168-173
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• 2005

Ag-doped $TiO_2$ thin films were prepared by RF magnetron co-sputtering method, and their physical and chemical properties were examined as a function of calcination temperature. XRD results showed that the crystallite size of Ag-doped films was smaller than that of the $TiO_2$ thin films. SEM results showed that the particle size of $Ag/TiO_2$ film was smaller and more uniform than pure $TiO_2$ film. The films had high transparency in the visible range. The films calcined at $600^{\circ}C$ were the anatase phase, and the films calcined at $900^{\circ}C$ were a mixture of anatase and rutile phases. The absorption edge of films calcined at $900^{\circ}C$ was red-shifted. This is due to the augmented absorption resulting from the phase transformation from anatase to rutile phase. And the transmittance of films decreased by the light scattering and absorption in the films. Photocatalytic activity of $Ag/TiO_2$ thin films was higher than that of the pure $TiO_2$ thin films.

• Korean Journal of Materials Research
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• v.17 no.3
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• pp.125-131
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• 2007

[ $TiO_{2}-solution$ ] was aaded in $SiO_{2}-solution$ by various composition. $SiO_{2}-TiO_{2}$ thin films were obtained by the dip-coating method on the $SiO_{2}$ glass substrates, and then heat-treated at various temperature. Nano-size $TiO_{2}$ particles dispersed $SiO_{2}-TiO_{2}$ films showed absorption peak by quantum size effect at short wavelength region $350{\sim}400nm$, which made them good candidates for non-linear optical materials and photo-catalytic materials. The thickness of $SiO_{2}-TiO_{2}$ films were $300{\sim}430nm$. The contact angle of $SiO_{2}-TiO_{2}$ films for water was $5.3{\sim}47.9^{\circ}$, and therefore it is clear that $SiO_{2}-TiO_{2}$ films have super hydrophilic properties and the self-cleaning effects.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1850-1852
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• 2005

$SrTiO_3$ and $BaTiO_3$ sol-liquids and powders were prepared by the sol-gel method. $SrTiO_3/BaTiO_3$ heterolayered thin/thick films have been prepared on the $Al_2O_3$ substrates by screen printing and spin-coating method. The thin films were sintered at $750^{\circ}C$ in the air for 1 hour and the thick films sintered at $1325^{\circ}C$ in the air for 2 hours, respectively. The $SrTiO_3/BaTiO_3$ thin/thick films's structural and dielectric properties were investigated. Increasing the spin-coating times, (110), (200), (211) peaks of the $SrTiO_3$ were increased. The X-ray diffraction(XRD) patterns and SEM photographs indicated that the $SrTiO_3$ phase were formed in the surface of $BaTiO_3$ thick films. The average thickness of a $BaTiO_3$ thick films and $SrTiO_3$ thin films were $50{\mu}m$ and 400nm, respectively The dielectric constant and dielectric loss of the $SrTiO_3/BaTiO_3$ thin/thick films with $SrTiO_3$ coated 5 times were 1598 and 0.0436 at 10KHz.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.5
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• pp.294-297
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• 2016

Titanium oxide ($TiO_2$) thin films were fabricated by unbalanced magnetron (UBM) sputtering. The fabricated $TiO_2$ films were treated by oxygen plasma under various RF powers. We investigated the characteristics of oxygen plasma treatment on the surface, structural, and physical properties of $TiO_2$ films prepared at various plasma treatment RF powers. UBM sputtered $TiO_2$ films exhibited higher contact angle value, smooth surface, and amorphous structure. However, the rms surface roughness $TiO_2$ films were rough, and the contact angle value was decreased with the increase of the plasma treatment RF power Also, the hardness value of $TiO_2$ film as physical properties was slightly increased with the increase of the plasma treatment RF power. In the results, the performance of $TiO_2$ films for self cleaning critically depended on the with the plasma treatment RF power.