• Transactions on Electrical and Electronic Materials
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• 제14권2호
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• pp.94-100
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• 2013

The elements B, P and As can each be implanted in silicon; for the fabrication of integrated semiconductor devices and the wells in CMOS (complementary metal oxide semiconductor). The implanted range due to different implanted species calculated using TRIM (Transport of Ions in Matter) simulation results was considered. The profiles of implanted samples could be measured using SIMS (secondary ion mass spectrometry). In the comparison between the measured and simulated data, some deviations were shown in the profiles of MeV implanted silicon. The Moliere, C-Kr, and ZBL potentials were used for the range calculations, and the results showed almost no change in the MeV energy region. However, the calculations showed remarkably improved results through the modification of the electronic stopping power. The results also matched very well with SIMS data. The calculated tolerances of $R_p$ and ${\Delta}R_p$ between the modified $S_e$ of TRIM and SIMS data were remarkably better than the tolerances between the TRIM and SIMS data.

• 멤브레인
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• 제25권6호
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• pp.488-495
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• 2015

Trimethylamine과 chloromethyl ethyl ether를 사용하여 PPO를 기반으로 하는 APPO를 제조하여 특성평가를 진행하였다. 전기 물리적 특성을 알아보기 위해 8 wt%의 APPO chloroform 용액으로 APPO막을 제막하여 특성평가를 진행하였다. 접촉각은 $44.4^{\circ}$, 함수율은 37.9%의 결과값을 얻을 수 있었다. 전기적 특성인 이온교환용량과 이온전도도는 각각 2.3 meq/g, 0.027 S/cm로 측정되었다. 또 time-lag 장치를 이용하여 단일기체(질소, 산소, 메탄, 이산화탄소, 이산화황)에 대한 확산도 및 용해도를 알아보았다. 산성가스인 이산화탄소와 황산의 경우, 투과도는 각각 20.7, 511.5 barrer로 측정되었다. 선택도의 경우, 이산화탄소/메탄은 39.8, 이산화탄소/질소는 42.2, 이산화황/이산화탄소는 24.7로 측정되었다.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.1-7
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• 2018

이산화주석은 리튬 이온 전지의 Anode 전극물질, 또는 $H_2$, NO, $NO_2$ 등의 가스 분자가 표면에 흡착되면 전기저항이 변하는 특성을 이용하여 가스센서로 활용되고 있으며, 나노구조를 갖는 이산화주석의 합성과 관련하여 많은 연구가 활발하게 이루어지고 있다. 나노구조물의 경우 Bulk 상태보다 체적 대비 표면적비가 높기 때문에 기체분자의 흡착확률을 높일 수 있으므로 고감도 가스 센서의 구현이 가능하고, Li-ion 이차전지의 경우에도 비정전용량을 향상시킬 수 있다. 본 연구에서는 열화학기상증착 장비를 이용하여 기상수송방법으로 $SnO_2$ 나노구조물을 Si 기판 위에 직접 성장시켰다. 이때 이송가스로 이용되는 고순도 Ar 가스에 고순도 산소가스를 혼합하였고, 산소가스의 혼합량에 따라 다른 형태의 산화주석 나노구조물이 성장되는 것을 확인하였다. 기상수송방법으로 성장된 산화주석 나노구조물의 결정학적 특성은 Raman 분광학 및 XRD 분석을 통하여 확인하였고, 표면형상을 주사전자현미경을 통하여 확인하였다. 분석결과 산화주석 나노구조물은 산소가스 혼합량에 민감하게 영향을 받았으며, 이송가스로 이용되는 고순도 Ar 1000 SCCM에 고순도 산소가스 10 SCCM을 혼합하였을 때, 적당한 두께를 가지면서 Nanodots 형태의 표면형상을 갖는 $SnO_2$ 결정상의 나노구조물이 성장되는 것을 확인하였다.

• Journal of Electrochemical Science and Technology
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• 제9권3호
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• pp.212-219
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• 2018

Perovskite type ceramic membranes which exhibit dual ion conduction (proton and oxygen ion conduction) can permeate water and can aid solving operational problems such as temperature gradient and carbon deposition associated with a working solid oxide fuel cell. From this point of view, it is crucial to reveal water transport mechanism and especially the nature of the surface sites that is necessary for water incorporation and evolution. $BaCe_{0.8}Y_{0.2}O_{3-{\alpha}}$ (BCY20) was used as a model proton and oxygen ion conducting membrane in this work. Four different catalytically modified membrane configurations were used for the investigations and water flux was measured as a function of temperature. In addition, CO was introduced to the permeate side in order to test the stability of membrane against water and $CO/CO_2$ and post operation analysis of used membranes were carried out. The results revealed that water incorporation occurs on any exposed electrolyte surface. However, the magnitude of water permeation changes depending on which membrane surface is catalytically modified. The platinum increases the water flux on the feed side whilst it decreases the flux on the permeate side. Water flux measurements suggest that platinum can block water permeation on the permeate side by reducing the access to the lattice oxygen in the surface layer.

• 한국재료학회지
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• 제13권3호
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• pp.191-194
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• 2003

The influence of on ion beam irradiation to the indium tin oxide (ITO) substrate on the performance of the organic light-emitting diodes (OLEDs) was studied. ITO films were used as the transparent anode of OLEDs with poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) as a hole-injection/transport layer. Oxygen and argon plasma treatment of ITO resulted in a change in the work function and the chemical composition. For plasma treated ITO anodes, the device efficiency clearly correlated with the value of the work function. We also discussed the implications of our experimental study in relation to the modification of the ITO surface composition, transmittance, reflectance, and water contact angle (WCA).

• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.320-325
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• 2023

In Li-ion batteries, a thick electrode is advantageous for lowering the inactive current collector portion and obtaining a high energy density. One of the critical failure mechanisms of thick electrodes is inhomogeneous lithiation and delithiation owing to the axial location of the electrode. In this study, it was confirmed that the top layer of the composite electrode contributes more to the charging step owing to the high ionic transport from the electrolyte. A high-loading multilayered electrode containing LiFePO₄ (LFP) and LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) was developed to overcome the inhomogeneous electrochemical reactions in the electrode. The electrode laminated with LFP on the top and NCM811 on the bottom showed superior cyclability compared to the electrode having the reverse stacking order or thoroughly mixed. This improvement is attributed to the structural and interfacial stability of LFP on top of the thick electrode in an electrochemically harsh environment.

• 대한금속재료학회지
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• 제49권10호
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• pp.818-822
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• 2011

ZnO nanorods were grown on Au-coated Si substrates by vapor phase transport (VPT) at the growth temperature of $600^{\circ}C$ using a mixture of zinc oxide and graphite powders as source material. Au thin films with the thickness of 5 nm were deposited by ion sputtering. Temperature-dependent photoluminescence (PL) was carried out to investigate the optical properties of the ZnO nanorods. Five peaks at 3.363, 3.327, 3.296, 3.228, and 3.143 eV, corresponding to the free exciton (FX), neutral donor bound exciton ($D^{\circ}X$), first order longitudinal optical phonon replica of free exciton (FX-1LO), FX-2LO, and FX-3LO emissions, were obtained at low-temperature (10 K). The intensity of these peaks decreased and their position was red shifted with the increase in the temperature. The FX emission peak energy of the ZnO nanorods exhibited an anomalous behavior (red-blue-red shift) with the increase in temperature. This is also known as an "S-shaped" emission shift. The thermal activation energy for the exciton with increasing temperature in the ZnO nanorods is found to be about 26.6 meV; the values of Varshni's empirical equation fitting parameters are = $5{\times}10^{-4}eV/K$, ${\beta}=350K$, and $E_g(0)=3.364eV$.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.476-480
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• 2009

본 연구는 리튬 이차전지용 고분자 전해질 복합재료에 관한 것으로, 고분자는 poly(ethylene oxide)(PEO)와 poly(methyl methacrylate) (PMMA) 블렌드를 사용하고, 용매로는 Ethylene carbonate(EC), 그리고 $LiClO_4$를 리튬염으로 하는 전해질 복합체 필름을 제조하였으며, PMMA의 함유량에 따른 고분자 전해질의 전기화학적 특성을 관찰하였다. 제조된 고분자 전해질의 결정화도와 이온전도도는 시차주사열량계(DSC)와 주파수반응분석기(FRA)로 분석하였다. 그 결과 PMMA의 함량을 증가시킴에 따라서, PEO의 결정 영역이 감소하고 이온전도도가 증가하였다. 또한, PMMA의 함량이 20 wt.% 이상인 경우, 고분자 블렌드필름에서 상분리되는 현상을 관찰하였다. 즉, SEM 분석결과에 의해서, PMMA 주성분 영역과 PEO 주성분 영역의 구분이 가능하였다. 고분자 전해질의 이온전도도는 20 wt.% 첨가한 경우 가장 큰 이온전도도를 가지며, 함유량이 20 wt.% 이상에서는 PMMA 상의 증가로 인해 다소 감소된 이온전도도 변화를 나타내었다.

• 멤브레인
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• 제28권4호
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• pp.260-264
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• 2018

올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparticles (AgNPs)(전구체: $AgBF_4$)/p-benzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지되는 것이 관찰되었다. 분리막의 성능이 100시간까지 유지할 수 있었던 이유는 p-BQ의 첨가로 인해 Ag ion이 안정적으로 Ag nanoparticles로 형성될 수 있었을 뿐더러 전자수용체인 p-BQ으로 인해 표면이 부분 양극성화 되어 올레핀 운반체로서 역할을 성공적으로 수행한 결과라 생각되었다. 본 연구에서는 Ag nanoparticles의 전구체로 사용된 $AgBF_4$의 가격이 고가이기 때문에 가격 측면에서 유리한 $AgNO_3$ Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과로서 $AgNO_3$의 경우에는 앞선 $AgBF_4$과는 다르게 안정적으로 은 나노입자가 형성되지 못하고 이로 인하여 좋은 성능을 내지 못하는 것으로 분석되었다.

• 한국세라믹학회지
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• 제49권5호
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• pp.404-411
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• 2012

The reliability of solid oxide fuel cells (SOFCs) particularly depends on the high quality of solid oxide electrolytes. The application of thinner electrolytes and multi electrolyte layers requires a more reliable characterization method. Most of the investigations on thin film solid electrolytes have been made for the parallel transport along the interface, which is not however directly related to the fuel cell performance of those electrolytes. In this work an array of ion-blocking metallic Ti/Au microelectrodes with about a $160{\mu}m$ diameter was applied on top of an ultrathin ($1{\mu}m$) yttria-stabilized-zirconia/gadolinium-doped-ceria (YSZ/GDC) heterolayer solid electrolyte in a micro-SOFC prepared by PLD as well as an 8-${\mu}m$ thick YSZ layer by screen printing, to study the transport characteristics in the perpendicular direction relevant for fuel cell operation. While the capacitance variation in the electrode area supported the working principle of the measurement technique, other local variations could be related to the quality of the electrolyte layers and deposited electrode points. While the small electrode size and low temperature measurements increaseed the electrolyte resistances enough for the reliable estimation, the impedance spectra appeared to consist of only a large electrode polarization. Modulus representation distinguished two high frequency responses with resistance magnitude differing by orders of magnitude, which can be ascribed to the gadolinium-doped ceria buffer electrolyte layer with a 200 nm thickness and yttria-stabilized zirconia layer of about $1{\mu}m$. The major impedance response was attributed to the resistance due to electron hole conduction in GDC due to the ion-blocking top electrodes with activation energy of 0.7 eV. The respective conductivity values were obtained by model analysis using empirical Havriliak-Negami elements and by temperature adjustments with respect to the conductivity of the YSZ layers.