• 한국세라믹학회지
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• 제42권12호
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• pp.787-792
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• 2005

A symmetrical LSCF $(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-\delta})\;ScSZ(89ZrO_2-10Sc_2O_3-1CeO_2)/LSCF$ electrochemical cell with a GDC (Gadolinium-Doped Ceria, $90CeO_2-10Gd_2O_3$) interlayer that was inserted between the LSCF cathode and ScSZ electrolyte was fabricated, and the electrochemical performance of these cells was evaluated. The GDC interlayer was deposited on a ScSZ electrolyte using a screen-printing technique. The GDC interlayer prevented the unfavorable solid-state reactions at the LSCF/ScSZ interfaces. The LSCF cathode on the GDC interlayer had excellent electrocatalytic performance even at $650^{\circ}C$. The Area Specific Resistance (ASR) was strongly dependent on the thickness and heat-treatment temperature of the GDC interlayer. The impedance spectra showed that the cell with a $15\~27{\mu}m$ thick GDC interlayer heat-treated at $1200^{\circ}C$ had the lowest ASR.

• Journal of Magnetics
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• 제10권2호
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• pp.52-57
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• 2005

In this research, magnetoresistance (MR) ratio (MR), resistivity, and exchange coupling field $(H_{ex})$ behaviors for sputter deposited spin valves with FeMn antiferromagnetic layer have been extensively investigated by rapid thermal annealing (RTA) as well as conventional annealing (CA) method. 10 s of RTA revealed that interdiffusion was not significant up to $325^{\circ}C$ at the interfaces between the layers when the RTA time was short. The MR of FeMn spin valves were reduced when the spin valves were exposed to temperature of $250^{\circ}C$, even for a short time period of 10 s prior to CA. $H_{ex}$ was maintained up to $325^{\circ}C$ of CA when the specimen was subjected to 10 s of RTA at $200^{\circ}C$ prior to CA, which is $25^{\circ}C$ higher than the result obtained from the CA without prior RTA. Therefore, the stability of $H_{ex}$ could be enhanced by a prior RTA before performing CA up to annealing temperature of $325^{\circ}C$. MR and sensitivity of the specimens annealed without magnetic field up to $275^{\circ}C$ were recovered to the values prior to CA, but $H_{ex}$ was not recovered. This means that reduced MR sensitivity and MR during the device fabrication can be recovered by a field RTA.

• Journal of Magnetics
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• 제19권2호
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• pp.140-145
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• 2014

The electrical transport properties of YBCO single layers thin film have been investigated using different physical techniques. For the purpose, the physical properties are probed numerically with help of simulation modelling. The physical transport properties were also estimated with temperature and magnetic fields limits using thermally-activated flux flow model with some modifications. The result of present simulation modelling indicated that the magnitude of activation energy depends on temperature and magnetic field. The simulations revealed thickness dependent physical transport properties including electrical and magnetic properties of deposited YBCO single layers thin films. Furthermore, it shows the temperature dependence of the pinning energy. In the nutshell, the result can be used to improve the Superconducting Properties ($T_c$) of the YBCO single layers thin films.

• Macromolecular Research
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• 제17권1호
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• pp.31-36
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• 2009

Highly transparent, thin polythiophene (PT) films were successfully synthesized by the plasma polymerization of thiophene. These films were doped with $O_2$ plasma by in-situ doping technique. The plasma polymerized PT films were deposited at about 50 to 340 nm/min, depending on the temperature and plasma power. A resultant transparency as high as 85% was achieved. The plasma polymerized PT films exhibited the characteristics of an insulator or semiconductor ($10^{10{\sim}12}{\Omega}/{\Box}$, $10^{-7}S/cm$). The conductivity was immediately increased up to $10{\Omega}/{\Box}$ and $10^{-2}S/cm$, when doped with $O_2$ plasma. The plasma-doped PT films exhibited an increased surface roughness resulting in a decreased contact angle. However, the thickness of the PT layer was partially decomposed and/or etched with increasing voltage above 40 W.

• Current Optics and Photonics
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• 제1권4호
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• pp.372-377
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• 2017

We demonstrate that the local resonance of metamaterials can be tuned by the effects of organic thin films under photoexcitation. Tris (8-hydroxyquinolinato) aluminum ($Alq_3$) layers are deposited on metamaterial/silicon hybrid structures. By varying the thickness of the $Alq_3$ layer on the subwavelength scale, the resonant peak of the metamaterial becomes very adjustable, due to the effect of a thin dielectric substrate. In addition, under photoexcitation all the spectral peaks of the resonance shift to higher frequencies. This originates from the reduction of the capacitive response generated inside the gaps of split-ring resonators. The adjustability of the electromagnetic spectrum may be useful for developing optical systems requiring refractive-index engineering and active optical devices.

• 한국재료학회지
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• 제15권8호
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• pp.514-517
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• 2005

Effects of nitrogen and oxygen annealing on the carrier concentration, carrier mobility, electrical resistivity and PL characteristics as well as the crystallinity of ZnO films deposited on sapphire substrates by atomic layer deposition (ALD). X-ray diffraction (XRD), Scanning electron microscope (SEM), photoluminescence (PL) analyses, and Hall measurement were performed to investigate the crystallinity, optical properties and electrical properties of the ZnO thin films, respectively. According to the XRD analysis results the crystallinity of the ZnO film annealed in an oxygen atmosphere is better than that of the ZnO film annealed in a nitrogen atmosphere. Annealing undoped ZnO films grown by ALD at a high temperature above $600^{\circ}C$ improves the crystallinity and enhances W emission but deteriorates the electrical conductivity of the flms. The resistivity of the ZnO film annealed particularly at $800^[\circ}C$ in a nitrogen atmosphere is much higher than that annealed at the same temperature in an oxygen atmosphere.

• 한국재료학회지
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• 제18권5호
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• pp.272-276
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• 2008

In submicron MOSFET devices, maintaining the ratio between the channel length (L) and the channel depth (D) at 3 : 1 or larger is known to be critical in preventing deleterious short-channel effects. In this study, n-type SOI-MOSFETs with a channel length of $0.1\;{\mu}m$ and a Si film thickness (channel depth) of $0.033\;{\mu}m$ (L : D = 3 : 1) were virtually fabricated using a TSUPREM-4 process simulator. To form functioning transistors on the very thin Si film, a protective layer of $0.08\;{\mu}m$-thick surface oxide was deposited prior to the source/drain ion implantation so as to dampen the speed of the incoming As ions. The p-type boron doping concentration of the Si film, in which the device channel is formed, was used as the key variable in the process simulation. The finished devices were electrically tested with a Medici device simulator. The result showed that, for a given channel doping concentration of $1.9{\sim}2.5\;{\times}\;10^{18}\;cm^{-3}$, the threshold voltage was $0.5{\sim}0.7\;V$, and the subthreshold swing was $70{\sim}80\;mV/dec$. These value ranges are all fairly reasonable and should form a 'magic region' in which SOI-MOSFETs run optimally.

• Nuclear Engineering and Technology
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• 제27권1호
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• pp.18-24
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• 1995

모래 입자를 대상으로 PVA-PMAA 계의 방사능 고정화 특성을 연구하였다. PMAA의 카르복시기는 PVA에 의해 해리가 억제되는 경향을 나타내었다. PMAA의 농도가 0.082M 이하일 때, PVA-PMAA로 처리한 모래층의 투과율은 혼합 용액내에 존재하는 PMAA의 농도에 정비례하고, 실험으로부터 얻은 비례 상수(k)는 -8.95$\times$10￣$^4$$cm^{5}$ /mole 이다. 투과도의 변화를 두 고분자 사이의 상호 작용에 의해 거대 분자간 착물이 형성됨에 의한 것으로 설명할 수 있었다. 모래 표면에 형성된 고분자 가교는 모래 입자들을 더욱 견고하게 부착시키는 것으로 나타났다. 본 계의 이온성 방사성 핵종에 대한 고정화 능력은 PVA를 단독 적용한 경우에 비하여 우수하다.

• 대한기계학회논문집B
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• 제30권12호
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• pp.1211-1217
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• 2006

This study is focused on oxidation prevention of STS430, which is generally used as solid oxide fuel cell(SOFC) interconnect at intermediate operating temperatures with oxidation-proof coatings. Inconel, $La_{0.6}Sr_{0.4}CoO_3(LSCo)$ and $La_{0.6}Sr_{0.4}CoO_3(LSCr)$ were chosen as coating materials. Using a radio frequency magnetron sputtering method, each target material was deposited as thin film on STS430 and was analyzed to find out favorable conditions. In this study, LSCr-coated STS430 can reduce electrical resistance to 1/3 level, compared with uncoated STS430. Also, long-term durability test at $700^{\circ}C$ for 1000 hours tells that LSCr thin layer performs an important role to prohibit serious degradations. Superior oxidation-resistant characteristic of LSCr-coated STS430 is attributed to the inhibition of spinel structure formation such as $MnCr_2O_4$.

• 태양에너지
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• 제8권1호
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• pp.41-48
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• 1988

Heterojunction solar cells of $n-Cd_{1-x}Zn_xS/p-Si$ were fabricated by solution growth technique. The crystal structure, spectral response, surface morphology, and I-V characteristics of the $n-Cd_{1-x}Zn_xS/p-Si$ heterojunction solar cells were studied. The $Cd_{1-x}Zn_xS$ layer deposited on a silicon substrate (111) were found to be a cubic structure with the crystal orientation (111), (220) of the CdS and to be a hexagonal structure with crystal orientation (100) of the ZnS. The open-circuit voltage, short-circuit current, fill factor, and conversion efficiency of $n-Cd_{1-x}Zn_xS/p-Si$ heterojunction solar cell under $100mW/cm^2$ illumination were found to be 0.43V, 38mA. 0.76, and 12.4%, respectively.