• 전기화학회지
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• 제15권3호
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• pp.149-153
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• 2012

The $Cu_2O/TiO_2$ inverse opal heterojunction arrays were developed by electrochemical deposition of $Cu_2O$ nanoparticles on $TiO_2$ inverse opal arrays. The $Cu_2O$ nanoparticles completely filled the inner pores of $TiO_2$ inverse opal film (prepared by liquid phase deposition with an average thickness of 400 nm) and covered the entire area; exhibiting high crystalline properties of anatase and cubic phase from $TiO_2$ and $Cu_2O$, respectively. From asymmetric current-voltage profile, it was noticeable that a heterojunction was well formed for charge transport from $Cu_2O$ to $TiO_2$ film resulting from the enhanced charge separation yield. In addition, increased photocurrent of 0.19 $mA/cm^2$ (versus 0.08 $mA/cm^2$ under dark condition) was obtained at -0.35 V from the heterojunction structure in the 0.5M $Na_2SO_4$ solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.969-972
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• 2004

Al doped Zinc Oxide(ZnO:Al) films, which is widely used as a transparent conductor in optoelectronic devices such as solar cell, liquid crystal display, plasma display panel, thermal heater, and other sensors, were prepared by using the capacitively coupled DC magnetron sputtering method. In this paper the effect of doping amounts of $Al_2O_3$ on the electrical, optical and morphological properties were investigated experimentally, The results show that the structural and electrical properties of the film are highly affected by the doping. The optimum growth conditions were obtained for films doped with 2 wt% of Al203 which exhibit a resistivity of $8.5{\times}10^{-4}{\Omega}-cm$ associated with a transmittance of 91.7 % for 840 nm in film thickness in the wavelength range of the visible spectrum.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.143-146
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• 2003

Al doped Zinc Oxide(ZnO:Al) films, which is widely used as a transparent conductor in optoelectronic devices such as solar cell, liquid crystal display, plasma display panel, thermal heater, and other sensors, were prepared by using the capacitively coupled DC magnetron sputtering method. The influence of the substrate temperature, working gas pressure and discharge power on the electrical, optical and morphological properties were investigated experimentally. The consideration on the effect of doping amounts of Al on the electrical and optical properties of ZnO thin film were also carried out. ZnO:Al films with the optimum growth conditions showed resistivity of $9.42{\times}10^{-4}\;{\Omeg}-cm$ and transmittance of 90.88% for 840nm in film thickness in the wavelength range of the visible spectrum.

• 한국세라믹학회지
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• 제42권4호
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• pp.219-223
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• 2005

A promising capacitor, which has conformable step coverage and good uniformity of thickness and composition, is needed to manufacture high-density non-volatile FeRAM capacitors with a stacked cell structure. In this study, ferroelectric $Bi_{3.61}Nd_{0.39}Ti_3O_{12}$ (BNdT) thin films were prepared on $Pt(111)/TiO_2/SiO_2/Si$ substrates by the liquid delivery system MOCVD method. In these experiments, $Bi(ph)_{3}$, $Nd(TMHD)\_{3}$ and $Ti(O^iPr)_{2}(TMHD)_{2}$ were used as the precursors and were dissolved in n-butyl acetate. The BNdT thin films were deposited at a substrate temperature and reactor pressure of approximately $600^{\circ}C$ and 4.8 Torr, respectively. The microstructure of the layered perovskite phase was observed by XRD and SEM. The remanent polarization value (2Pr) of the BNdT thin film was $31.67\;{\mu}C/cm^{2}$ at an applied voltage of 5 V.

• 한국자기학회지
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• 제17권6호
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• pp.246-252
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• 2007

본 논문에서는 출발원료 배합비 및 육성 파라미터가 LPE(Liquid Phase Epitaxy)법으로 육성된 자성 가넷 막의 특성에 미치는 영향을 조사하며, 광 CT의 페러데이 회전자용으로서 적합한 막의 육성 조건을 제시한다. 막을 평가하기 위하여 조사한 특성은 막후, 표면 모폴로지, X선 회절, 격자상수, 막과 기판(단결정 비자성 가넷 웨이퍼)사이의 격자상수의 부정합, 페러데이 회전각 등이었다. 또한, 육성된 자성 가넷 막을 이용하여 광 CT를 제작하고, 성능을 평가했다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.12-13
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• 2006

Ferroelectric Cerium-substituted $Bi_4Ti_3O_{12}$ thin films with a thickness of 200 nm were deposited using the liquid delivery metal organic chemical vapor deposition process onto a Pt(111)/Ti/$SiO_2$/Si(100) substrate. At annealing temperature above $600^{\circ}C$, the BCT thin films became crystallized and exhibited a polycrystalline structure. The BCT thin film annealed at $720^{\circ}C$ showed a large remanent polarization ($2P_r$) of $44.56\;{\mu}C/cm^2$ at an applied voltage of 5V. The BCT thin film exhibits a good fatigue resistance up to $1{\times}10^{11}$ switching cycles at a frequency of 1 MHz with applied electric field of ${\pm}5\;V$.

• 한국세라믹학회지
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• 제39권6호
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• pp.589-593
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• 2002

Bi:Y$_3$Fe$_{5}$ $O_{12}$(Bi:YIG)를 (GdCa)$_3$(GaMgZr)$_{5}$ $O_{12}$(SGGG)기판 위에 Liquid Phase Epitaxy(LPE)법으로 단결정 후막을 성장시켰다 기판회전속도, 과냉도, 성장시간을 고정하여 PO/Bi$_2$ $O_3$ 몰 비 변화에 따른 성장된 가네트 결정의 격자상수 변화와 Bi 농도 분포를 조사하였다. PO/Bi$_2$ $O_3$ 몰 비가 감소함에 따라 성장된 가네트 결정의 격자상수하 Bi 농도는 증가하는 경향이 나타났으나, 가네트 결정의 두께가 증가됨에 따라 Bi 농도는 감소하는 경향이 나타났다.

• 마이크로전자및패키징학회지
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• 제29권2호
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• pp.33-41
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• 2022

최근 플렉시블 전자소자의 안정적인 전기적 연결을 위한 유연전도성 접합 기술의 연구 필요성이 대두되고 있다. 기존의 금속 납땜 접합에서 발생하는 기계적 파손 문제는 탄성 계수가 작거나 두께가 얇은 재료를 기반으로 제작된 유연전도성 접합을 통해 해결할 수 있다. 기계적 특성을 향상시키는 동시에 안정적인 전기적 연결이 가능하도록 높은 전기전도도를 가진 물질을 박막화하거나, 작은 탄성 계수를 가진 물질에 혼합하는 방식 등으로 형성된다. 대표적인 유연전도성 접합 기술로는 박막 증착을 통한 유연전도성 접합, 유연 전도성 접착제 기반 접합, 그리고 액체 금속 기반의 전도성 접합 형성 방법 등이 있으며 본 논문에서는 각 방법들의 기계적/전기적 특성 향상 전략과 그 쓰임을 소개한다.

• 전기화학회지
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• 제14권2호
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• pp.117-124
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• 2011

We demonstrate a new surface modification of high-voltage lithium cobalt oxide ($LiCoO_2$) cathode active materials for lithium-ion batteries. This approach is based on exploitation of a polarity-tuned gel polymer electrolyte (GPE) coating. Herein, two contrast polymers having different polarity are chosen: polyimide (PI) synthesized from thermally curing 4-component (pyromellitic dianhydride/biphenyl dianhydride/phenylenediamine/oxydianiline) polyamic acid (as a polar GPE) and ethylene-vinyl acetate copolymer (EVA) containing 12 wt% vinyl acetate repeating unit (as a less polar GPE). The strong affinity of polyamic acid for $LiCoO_2$ allows the resulting PI coating layer to present a highly-continuous surface film of nanometer thickness. On the other hand, the less polar EVA coating layer is poorly deposited onto the $LiCoO_2$, resulting in a locally agglomerated morphology with relatively high thickness. Based on the characterization of GPE coating layers, their structural difference on the electrochemical performance and thermal stability of high-voltage (herein, 4.4 V) $LiCoO_2$ is thoroughly investigated. In comparison to the EVA coating layer, the PI coating layer is effective in preventing the direct exposure of $LiCoO_2$ to liquid electrolyte, which thus plays a viable role in improving the high-voltage cell performance and mitigating the interfacial exothermic reaction between the charged $LiCoO_2$ and liquid electrolytes.

• Current Optics and Photonics
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• 제3권1호
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• pp.66-71
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• 2019

Application of liquid crystal (LC) materials to a flexible device is challenging because the bending of LC displays easily causes change in thickness of the LC layer and orientation of LCs, resulting in deterioration in a displayed image quality. In this work, we demonstrate a prototype device combining a flexible polymer substrate and an optically isotropic LC-polymer composite in which the device consists of interdigitated in-plane switching electrodes deposited on a flexible colorless polyimide substrate and the composite consisting of nano-sized LC droplets in a polymer matrix. The device can keep good electro-optic characteristics even when it is in a bending state because the LC orientation is not disturbed in both voltage-off and -on states. The proposed device shows a high potential to be applicable for future flexible LC devices.