• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1211-1216
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• 1989

To enhance the breakdown properties of low voltage-oriented ZnO varistor, sample were fabricated with additive oxides and sintering conditions. Addition of TiO2 lowered breakdown voltage` nonlinear resistances were lowered about 10V/mm and nonlinear exponents were not lowered with respect to it with the basic composition. To the samples added TiO2, V2ko5, and Cr2O3, microstructures were observed by SEM, moreover Ti was detected at grainboundaries and within the grain by EDS. Addition of Si-oxides and Sb2O3 increased nonlinear exponent and also increased nonlinear resistance, by addition of TiO2 to these samples at the sintering conditions of 1250\ulcorner and 1 hour we could fabricate low voltage-oriented ZnO varistors with nonlinear exponent of 30 or more and with real breakdown voltage of 30V/mm.

• Journal of the Korean institute of surface engineering
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• v.33 no.4
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• pp.251-260
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• 2000

Ta and Hf added Ti-l5Sn-4Nb alloys without V and Al elements for biomaterial were melted by arc furnace in response to recent concerns about the long term safety of Ti-6Al-4V alloy. All specimens were homogenized at $1000^{\circ}C$ and solution treatment was performed at $812^{\circ}C$ and aging treatment at $500^{\circ}C$. The microstructure and mechanical properties were analysed by optical micrograph, hardness tester and instron. Ti-l5Sn-4Nb system alloys showed widmanstatten microstructure which is typical microstructure in $\alpha$＋$\beta$ type Ti alloys. The Ti-l5Sn-4Nb-2Hf and Ti-l5Sn-4Nb-2Ta alloys showed better hardness and tensile strength compared with Ti-6Al-4V. The result of XPS analysis, Ti-l5Sn-4Nb alloy in air atmosphere consisted of $TiO_2$, SnO and NbO.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.826-832
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• 1998

In this study the thin films with the structure of Si+SiO$_2$+TiN are made by RF supttering method. TiN, which has small diffusion coefficient and low resistivity, is evaporated between SiO$_2$ and Al layers. It investigates the V-R characteristics depending on the thickness of SiO$_2$ which is used as insulation layer and researches its effects on voltage stability of thin film and varistor. These films show very small resistance valus in negative(-) voltage and large and large value in positive voltage band, and with the increase of voltage, resistance value is rapidly reduced and the satisfactory characteristic of varistor is shown at +1[V]. It is found that resistance value of TiN thin film is small and also TiN thin film has more current than the thin film which is not evaporated by TiN thin film. When Al electrode is evaporated of SiO$_2$ thin film, spiking occurs, but the spiking can be prevented with evaporation of TiN between SiO$_2$ and Al layers and this thin films in made easily because of its good attachment. With the increase of voltage, the resistance is changed into non-linear pattern and the bidirectional varistor characteristic is shown and then its theory can be verified by this experiment. Accordingly, when TiN is evaporated of Si Wafer(n-100), it obtains better voltage-resistance than thin film which is not evaporated and also when varistor character is used electrically to automatic control element such as elimination of flame, power distribution arrestor and constant voltage compensation, satisfactory reproducibilities are expected.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.7-11
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• 2000

The low-voltage driven $SrTiO_3$ceramic varistor device was fabricated from $SrTiO_3$ powders prepared by co-precipitation method with $CuO-SiO_2$additives. Compare with conventional process, this process has advantages such as the reduction of the sintering temperature of $SrTiO_3$ ceramics by 100-$150^{\circ}C$ and the simplification of processing procedure. The non-linear coefficient value ($\alpha$) of the varistor showed 8.47 when it was sintered at $1350^{\circ}C$ for 2 h with 5 wt% additives in reducing atmosphere of 5% $H_2/N_2$ mixed gas. The low-voltage driven $SrTiO_3$ceramic varistor was obtained which has a breakdown voltage as low as 7 V.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.327-331
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• 2009

Nano-porous $TiO_2$ powder was fabricated using Acetylene black, applied photo voltaic device based on the Dye-sensitized Solar Cells (DSCs) was investigated experimentally. $TiO_2$-powder was fabricated using Ti-isopropoxide and 2-propanol by sol-gel combustion method. For cases of variable Acetylene black, characteristic of porosity, size of particle and crystallite of obtained $TiO_2$ nano-powder was investigated. The photovoltaic efficiency of the prepared DSCs was measured using $TiO_2$ film which prepared on each different heat treatment temperature($400^{\circ}C{\sim}700^{\circ}C$) with paste of $TiO_2$ powder. The porosity and size of particle of $TiO_2$ powder made with Acetylene black 0.4g was influenced significantly effect to DSCs characteristic. Heat treatment at $500^{\circ}C$ makes the better photovoltaic efficiency which 5.02%($J_{sc}=11.79mA/cm^2$, $V_{oc}=0.73V$, ff=0.58). The sol-gel combustion method was useful to DSCs fabrication.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.115-116
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• 1992

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.333-340
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• 1996

The properties of TiN as a barrier against Cu diffusion ere studied by sheet resistance measurement, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and capacitance-voltage(C-V) measurement. The sensitivities of the various methods were compared. Specimens with Cu/TiN/Ti/SiO2/Si structure were prepared by various deposition techniques and annealed at various temperatures ranging from $500^{\circ}C$ to $800^{\circ}C$ in 10%H2/90%Ar ambient for hours. As the effectiveness of the barrier property of TiN against Cu diffusion was vanished, the irregular-shaped sports were observed and outdiffused Si were detected on the surface of the Cu thin film. The C-V characteristics of the MOS capacitors varied drastically with annealing temperatures. In C-V measurement, the inversion capacitance decreased at annealing temperature range from $500^{\circ}C$ to $700^{\circ}C$ and increased remarkably at $800^{\circ}C$. These variations may be due to the Cu diffusion through TiN into $SiO_2$ and Si.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.240-249
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• 1995

Rutile type of $TiO_{2}$ single crystal was grown by floating zone method in order to obtain the highly transparent and contamination-free single crystal. The linear refractive index of perpendicular and parallel to c-axis was measured as a function o f wavelength from 500 to 1000nm. The optical energy band gap was estimated as 2.99 eV from the absorption spectrum. The theoretical $\chi^{(3)}$} value of $TiO_{2}$ was discussed in comparison with that of $SiO_{2}$ quartz single crystal on the basis of semiempirical model. On the other hand, the second-hyperpolarizability, ${\gamma}({Ti}^{4+})$ was calculated in order to describe the effect of $Ti_{4}$ ion on the third order nonlinear optical properties.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.516-523
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• 2021

A study using selective catalytic reduction (SCR) was conducted in conjunction with ammonia as a reducing agent for controlling nitrogen oxides, a typical secondary inducer of fine dust in the atmosphere. For NH₃-SCR experiments, a commercial catalyst of V/W/TiO₂ only and also V/W-Sb/TiO₂ catalyst with Sb were used, and phosphorous durability was confirmed. As a result of NH₃-SCR experiments, it was confirmed that the addition of Sb to V/W/TiO₂ had durability against phosphorous. In addition, the physical and chemical properties were comparatively analyzed through BET, XPS, H₂-TPR, NH₃-TPD, and FT-IR analysis. From the anaylsis results, when Sb was added to V/W/TiO₂ catalyst, P was also added resulting in the formation of SbPO₄ and the generation of VOPO₄ was suppressed. The phosphorous durability was confirmed by maintaining the redox characteristics of the catalyst before P was added.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.420-423
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• 2003

[ $TiO_2$ ] thin films were fabricated by DC magnetron sputtering system at by controlling deposition times, ratios of $Ar:O_2$ partial presser ratio and substrate conditions. And the surface, cross-section morphology, microstructure, and composition ratio of the films were analyzed by FE-SEM, TEM and XPS. Besides, the optical absorption and transmittance of the $TiO_2$ films were measured by a UV-VIS-NIR Spectrophotometer, and photocatalytic properties were studied by G C Analyzer & Data Analysis system. As the result, when $TiO_2$ thin film was made at deposition time of 120[min] and $Ar:O_2$ ratio of 60:40, the best structural and optical properties among many thin films could be accepted. The best results of properties were as follows: thickness; $360{\sim}370[nm]$, grain size; 40[m], gap between two peak binding energy, $5.8{\pm}0.05[eV]$ ($2p_{3/2}$ peak and $2p_{1/2}$ peak of Ti was show at $458.3{\pm}0.05[eV]$ and $464.1{\pm}0.05[eV]$ respectively), binding energy; $530{\pm}0.05\;[eV]$, opticalenergy band gap; 3.4[eV].