• 센서학회지
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• 제7권5호
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• pp.364-371
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• 1998

Field programmable gate array (FPGA)의 전압 프로그램 요소(voltage programmable link)로써 사용될 새로운 안티퓨즈를 제조하였다. 제조된 안티퓨즈는 Al/$BaTiO_3/SiO_2$/TiW-실리사이드 구조를 갖는다. 안티퓨즈의 프로그램 전압은 $BaTiO_3$의 증착 두께를 조절함으로써 정확하게 조절할 수 있었다. $BaTiO_3(120{\AA})$/$SiO_2(120{\AA})$의 안티퓨즈에서 TiW-실리사이드 전극에 (-)극성을 인가하여 측정된 프로그램 전압은 14.4 V였으며, on-저항은 $40-50{\Omega}$의 값을 갖는다. 안티퓨즈의 전류-전압 특성은 Frenkel-Poole 전도 기구를 따르고 있으며, 그 특성은 인가 전압의 극성에 따라 차이를 보였다. 이것은 Al/$BaTiO_3$계면과 TiW-silicide/$SiO_2$계면 특성이 다르기 때문이다.

• 한국세라믹학회지
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• 제35권5호
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• pp.472-478
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• 1998

Ferroelectric SrBi2Ta2O9(SBT) films were deposited on Pt/Ti/SiO2/Si substrates at 50$0^{\circ}C$ using a sintered SBT target Bi and Ta targets by modified rf magnetron sputtering and then were annealed at 80$0^{\circ}C$ for 10min in oxygen ambinet(760 torr) The composition of the SBT films could be easily controlled using the mul-ti-targets. The film composition of {{{{ {Sr }_{0.8 } {Bi }_{2.9 } {Ta}_{2.0 } {O }_{9 } }} was obtained with SBTd sputtering power of 100 W Bi of 25W and Ta of 10 W. A 250nm thick SBT films exhibited a dense and uniform microstructure and showed the remanent polarization(Pr) of 14.4 $\mu$C/cm2 and the coercive field({{{{ {E }_{c } }})of 60 kV/cm at applied voltage of 5 V. The SBT films show practically no polarization fatigue up to {{{{ {10 }_{10 } }} cycles under 5V bipolar pulse. The retention characteristics of the SBT films looked very promising and the leakage current density of the SBT films was about 1.23$\times${{{{ {10 }^{-7 } }}A/c{{{{ {m }^{2 } }} at 120kV/cm.

• 한국표면공학회지
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• 제56권6호
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• pp.380-385
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• 2023

In this study, an MPB PMNT system containing 0.05 to 0.10 wt.% BaTiO₃ was synthesized using a traditional chemical method and its pyroelectricity was investigated. Pyroelectricity, dielectricity, and ferroelectricity of the synthesized BaTiO₃-PMNT system were analyzed by heat treatment at 1240~1280 ℃ for 4 hours to evaluate its applicability as a pyroelectric sensor. Unlike the simple ABO₃ ferroelectric, the BaTiO₃-doped PMNT system exhibited phase transition characteristics over a wide temperature range typical of complex perovskite structures. Although no dramatic change could be confirmed depending on the amount of BaTiO₃ added, stable pyroelectricity was maintained near room temperature and over a wide temperature range. When the amount of BaTiO₃ added increased from 0.05BaTiO₃-PMNT to 0.10BaTiO₃-PMNT, the electric field slightly increased from 5.00×10³ kV/m to 6.75×10³ kV/m, and the maximum value of remanent polarization slightly increased from 0.223 C/m² to 0.234 C/m². The pyroelectric coefficients of 0.05BaTiO₃-PMNT and 0.10BaTiO₃- PMNT at room temperature were measured to be ~0.0084 C/m²K and ~0.0043 C/m²K, respectively. The relaxor ferroelectric properties of the BaTiO₃-PMNT system were confirmed by analyzing the plot of K_max/K versus (T-T_max)^γ. The BaTiO₃-doped MPB PMNT system showed a distinct pyroelectric performance index at room temperature, and the values were F_v ~ 0.0362 m²/C, F_d ~ 0.575×10^-4 Pa^-1/2.

• 한국결정성장학회지
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• 제4권4호
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• pp.378-387
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• 1994

선행연구[1] 즉, $Ti0_2/Pb/TiO_2(900{\AA}/900{\AA}/900{\AA}/)$ 3층구조박막으로부터 열확산에 의해 상형성이 가능하였던 $PbTiO_3$ 박막의 특성을 개선하기 위하여 스퍼터링법을 이용하여 Si기판위에 각 요소층의 두께를 $200~300 {\AA}$으로 얇게하고 적층수를 3,5,7,9,11층$(TiO_2/Pb/.../Tio_2)$으로 변화시켜가며 다층구조박막을 형성한 후 이를 RTA 처리하여 $PbTiO_3$ 박막을 제조하였다. 그 결과 $500^{\circ}C$ 이상에서 단일상의 $PbTiO_3$가 형성되었다. 또한 요소층의 두께를 얇게하고 적층수를 늘려서 열처리한 결과 Pb-silicate 및 void 생성이 억제되어 우수한 계면상태를 유지하였으며 조성도 보다 균일해지는 양상을 나타내었다. $PbTiO_3$ 박막의 MiM구조에 C-V 특성으로부터 측정된 유전상수는 열처리 조건에 따른 경향을 나타내지 않았으나 적층수가 많아져 박막의 두께가 증가 할수록 유전상수가 증가하였다. MIS 구조의 $PbTiO_3$ 박막의 I-V 특성 측정 결과 절연파괴강도는 최고 150kV/cm이었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.75-78
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• 2002

The dielectric properties for Ni electrode multilayer ceramic chip capacitor for Y5V has been studied with $(Ba_{0.93}Ca_{0.07})_m(Ti_{0.82}Zr_{0.18})O_2+MnO_2$ 0.2wt%, $Y_2O_3$ 0.18wt%, $SiO_2$ 0.15wt%, glass frit 1 wt% composition. The m ratio in the range of 1.006 ~ 1.012 have dielectric constant 9,500 ~ 14,500 and insulation resistance 390 ~ 460 $G{\Omega}$. Using the dielectrics, nikel electrode multilayer chip capacitor with Y5V, 104Z in EIA 0603 size specific capacitance were developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.234-238
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• 1987

In this paper, the used specimen composition was added basic additives ($Bi_2O_3\;lmol%$, $Sb_2O_3\;lmol%$, CoO 0.5 mol%, MnO 0.5mol%) to ZnO powder, and $TiO_2$ (1,2,3,4 mol%) to the above basic composition. It appears that there are four regions of conduction current depended upon the strength of the applied electric field ; Ohimic region, Poole-Frenkel region, Schottky region and Tunneling region. Increasing of $TiO_2mol%$, the breakdown voltages of ZnO ceramic varistors are decreased. The decrease of breakdown voltages was explained with the decrease of potential barrier height. Moreover, V-I characteristics with temperature dependence are decreased with increasing of $TiO_2mol%$.

• 한국대기환경학회지
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• 제20권6호
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• pp.783-792
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• 2004

In this study, a thick-film semiconductor odor gas sensor for the detection of $CH_3$SH was developed using SnO$_2$ as the main substrate and was investigated in terms of its sensitivity and reaction time. In the process of manufacturing the sensor, Taguchi's design of experiment (DOE) was applied to analyze the effects of a variety of parameters, including the substrate, the additives and the fabrication conditions, systematically and effectively. Eight trials of experiments could be possible using the 27 orthogonal array for the seven factors and two levels of condition, which originally demands 128 trials of experiments without DOE. The additives of Sb$_2$O$_{5}$ and PdCl$_2$ with the H$_2$PtCl$_{6}$ ㆍ6$H_2O$ catalyst were appeared to be important factors to improve the sensitivity, and CuO, TiO$_2$, V$_2$O$_{5}$ and PdO were less important. In addition, TiO$_2$, V$_2$O$_{5}$ and PdO would improve the reaction time of a sensor, and CuO, Sb$_2$O$_{5}$, PdCl$_2$ and H$_2$PtCl$_{6}$ㆍ6$H_2O$ were negligible. Being evaluated simultaneously in terms of both sensitivity and reaction time, the sensor showed the higher performance with the addition of TiO$_2$ and PdO, but the opposite results with the addition of CuO, V$_2$O$_{5}$, Sb$_2$O$_{5}$ and PdCl$_2$. The amount of additives were superior in the case of 1% than 4%. H$_2$PtCl$_{6}$ㆍ6$H_2O$ would play an important role for the increase of sensor performance as a catalyst.nce as a catalyst.

• 한국재료학회지
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• 제31권2호
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• pp.92-96
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• 2021

We report the growth and enhanced photoelectrochemcial (PEC) water-splitting reactivity of few-layer MoS2 nanosheets on TiO2 nanowires. TiO2 nanowires with lengths of ~1.5 ~ 2.0 ㎛ and widths of ~50~300 nm are synthesized on fluorine-doped tin oxide substrates at 180 ℃ using hydrothermal methods with Ti(C4H9O)4. Few-layer MoS2 nanosheets with heights of ~250 ~ 300 nm are vertically grown on TiO2 nanowires at a moderate growth temperature of 300 ℃ using metalorganic chemical vapor deposition. The MoS2 nanosheets on TiO2 nanowires exhibit typical Raman and ultraviolet-visible light absorption spectra corresponding to few-layer thick MoS2. The PEC performance of the MoS2 nanosheet/TiO2 nanowire heterostructure is superior to that of bare TiO2 nanowires. MoS2/TiO2 heterostructure shows three times higher photocurrent than that of bare TiO2 nanowires at 0.6 V. The enhanced PEC photocurrent is attributed to improved light absorption of MoS2 nanosheets and efficient charge separation through the heterojunction. The photoelectrode of the MoS2/TiO2 heterostructure is stably sustained during on-off switching PEC cycle.

• The Korean Journal of Ceramics
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• 제2권3호
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• pp.131-136
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• 1996

The electrical conductivity of polycrystalline TiO2 samples was measured over the temperature range 1000°-1400℃ and from 0.21 to 10-16 atm of oxygen. Based on the excellent fit observed between the theoretically derived relatin σ3=(Aσ+B)Po2-1/2+D'σ2 and the experimental conductivity data, the nonstoichimetric defect structure of TiO2 was rationalized in terms of a defect model involving quasi-free electrons and both singly and doubly ionized oxygen vacancies. The standard enthalpy of formation for the following defect reactions in TiO2. (a) OO={{{{ { 1} over {2 } }}O2(g)+VO+e'; Δ{{{{ { H}`_{o } ^{a } }}=5.15(eV) (b) OO={{{{ { 1} over {2 } }}O2(g)+VO+2e'; Δ{{{{ { H}`_{0 } ^{ a} }}=6.30(eV) (c) VO=VO+e'; Δ{{{{ { H}`_{0 } ^{a } }}=1.15(eV) were determined from the temperature dependence of A and B obtained from the above relation and from the experimental expression between the electron mobility and temperature. The electrical conductivity of TiO2 in air below approximately 950℃ appears, on the basis of this investigation, to be impurity controlled due to the presence of aluminum rather than intrinsic conduction.

• 한국환경과학회지
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• 제14권2호
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• pp.221-230
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• 2005

Catalytic wet oxidation of trichloroethylene (TCE) in water has been conducted using $TiO_2-supported$ cobalt oxides at $36^{\circ}C$ with a weight hourly space velocity of $7,500\;h^{-1}.\;5\%\;CoO_x/TiO_2$, prepared by using an incipient wetness technique, might be the most promising catalyst for the wet oxidation although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. XPS spectra of both fresh and used Co surfaces gave different surface spectral features for each $CoO_x,\;Co\;2P_{3/2}$ binding energy for Co species in the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $CO_2TiO_4\;and\;CoTiO_3$. The used catalyst exhibited a 780.3-eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD patterns for $5\%\;CoO_x/TiO_2$ catalyst indicated that the phase structure of Co species in the catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present predominantly on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.