• 한국재료학회지
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• 제23권11호
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• pp.638-642
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• 2013

Chalcopyrite $CuInSe_2$(CIS) is considered to be an effective light-absorbing material for thin film photovoltaic solar cells. CIS thin films have been electrodeposited onto Mo coated and ITO glass substrates in potentiostatic mode at room temperature. The deposition mechanism of CIS thin films has been studied using the cyclic voltammetry (CV) technique. A cyclic voltammetric study was performed in unitary Cu, In, and Se systems, binary Cu-Se and In-Se systems, and a ternary Cu-In-Se system. The reduction peaks of the ITO substrate were examined in separate $Cu^{2+}$, $In^{3+}$, and $Se^{4+}$ solutions. Electrodeposition experiments were conducted with varying deposition potentials and electrolyte bath conditions. The morphological and compositional properties of the CIS thin films were examined by field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). The surface morphology of as-deposited CIS films exhibits spherical and large-sized clusters. The deposition potential has a significant effect on the film morphology and/or grain size, such that the structure tended to grow according to the increase of the deposition potential. A CIS layer deposited at -0.6 V nearly approached the stoichiometric ratio of $CuIn_{0.8}Se_{1.8}$. The growth potential plays an important role in controlling the stoichiometry of CIS films.

• Carbon letters
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• 제21권
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• pp.68-73
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• 2017

We have demonstrated the production of thin films containing multilayer graphene-coated copper nanoparticles (MGCNs) by a commercial electrodeposition method. The MGCNs were produced by electrical wire explosion, an easily applied technique for creating hybrid metal nanoparticles. The nanoparticles had average diameters of 10-120 nm and quasi-spherical morphologies. We made a complex-electrodeposited copper thin film (CETF) with a thickness of $4.8{\mu}m$ by adding 300 ppm MGCNs to the electrolyte solution and performing electrodeposition. We measured the electric properties and performed corrosion testing of the CETF. Raman spectroscopy was used to measure the bonding characteristics and estimate the number of layers in the graphene films. The resistivity of the bare-electrodeposited copper thin film (BETF) was $2.092{\times}10^{-6}{\Omega}{\cdot}cm$, and the resistivity of the CETF after the addition of 300 ppm MGCNs was decreased by 2% to ${\sim}2.049{\times}10^{-6}{\Omega}{\cdot}cm$. The corrosion resistance of the BETF was $9.306{\Omega}$, while that of the CETF was increased to 20.04 Ω. Therefore, the CETF with MGCNs can be used in interconnection circuits for printed circuit boards or semiconductor devices on the basis of its low resistivity and high corrosion resistance.

• 한국표면공학회지
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• 제49권1호
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• pp.40-45
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• 2016

Recently, $Bi_2Te_3$-based alloys are the best thermoelectric materials near to room temperature, so it has been researched to achieve increased figure of merit(ZT). Ternary compounds such as Bi-Te-Se and Bi-Sb-Te have higher thermoelectric property than binary compound Bi-Te and Sb-Te, respectively. Compared to DC plating method, pulsed electrodeposition is able to control parameters including average current density, and on/off pulse time etc. Thereby the morphology and properties of the films can be improved. In this study, we electrodeposited n-type ternary Cu-doped $Bi_2(Te-Se)_3$ thin film by modified pulse technique at room temperature. To further enhance thermoelectric properties of $Bi_2(Te-Se)_3$ thin film, we optimized Cu doping concentration in $Bi_2(Te-Se)_3$ thin film and correlated it to electrical and thermoelectric properties. Thus, the crystal, electrical, and thermoelectric properties of electrodeposited $Bi_2(Te-Se)_3$ thin film were characterized the XRD, SEM, EDS, Seebeck measurement, and Hall effect measurement, respectively. As a result, the thermoelectric properties of Cu-doped $Bi_2(Te-Se)_3$ thin films were observed that the Seebeck coefficient is $-101.2{\mu}V/K$ and the power factor is $1412.6{\mu}W/mK^2$ at 10 mg of Cu weight. The power factor of Cu-doped $Bi_2(Te-Se)_3$ thin film is 1.4 times higher than undoped $Bi_2(Te-Se)_3$ thin film.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.337-337
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• 2004

As one of researches for the P ＆ T purposes, a basic experiment on the recovery of actinide elements from the mixture with rare earth elements by means of electrorefining using a liquid cadmium cathode in the LiCl-KC1 eutectic melt was carried out. In order to examine the behaviors of electrodeposition of metal ions on a liquid electrode, recovery experiments of rare earth metals resulting from forming electrodeposits were performed by a galvanostatic electrolysis method at various current densities. A cyclic voltammetric technique was applied to determine reduction-oxidation potential of each metal element in the melt and to detect the changes of the multi component melt composition for on-line monitoring. Also, a collaboration study with RIAR was completed to test the preliminary feasibility on a recovery of actinide elements from the mixture with rare earth elements using a liquid cadmium cathode and actinide metals. Experimental results showed that the ratio of actinides to rare earths, 9: 0.5∼1 led to the rare earth content of about 5∼10 wt% in the deposit.

• 한국재료학회지
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• 제21권5호
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• pp.288-294
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• 2011

Simultaneous Ni and C codeposition by electrolysis was investigated with the aim of obtaining better corrosion resistivity and surface conductivity of a metallic bipolar plate for application in fuel cells and redox flow batteries. The carbon content in the Ni-C composite plate fell in a range of 9.2~26.2 at.% as the amount of carbon in the Ni Watt bath and the roughness of the composite were increased. The Ni-C composite with more than 21.6 at.% C content did not show uniformly dispersed carbon. It also displayed micro-sized defects such as cracks and crevices, which result in pitting or crevice corrosion. The corrosion resistance of the Ni-C composite in sulfuric acid is similar with that of pure Ni. Electrochemical test results such as passivation were not satisfactory; however, the Ni-C composite still displayed less than $10^{-4}$ $A/cm^2$ passivation current density. Passivation by an anodizing technique could yield better corrosion resistance in the Ni-C composite, approaching that of pure Ni plating. Surface resistivity of pure Ni after passivation was increased by about 8% compared to pure Ni. On the other hand, the surface resistivity of the Ni-C composite with 13 at.% C content was increased by only 1%. It can be confirmed that the metal plate electrodeposited Ni-C composite can be applied as a bipolar plate for fuel cells and redox flow batteries.

• 한국표면공학회지
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• 제48권6호
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• pp.260-268
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• 2015

The thermal barrier coating (TBC) for inner wall of liquid-fuel rocket combustor consists of NiCrAlY as bonding layer and $ZrO_2$ as a top layer. In most case, the plasma spray coating is used for TBC process and this process has inherent possibility of cracking due to large difference in thermal expansion coefficients among bonding layer, top layer and metal substrate. In this paper, we suggest crack-free TBC process by using a precise electrodeposition technique. Electrodeposited Ni-P/Cr double layer has similar thermal expansion coefficient to the Cu alloy substrate resulting in superior thermal barrier performance and high temperature oxidation resistance. We studied the effects of phosphorous concentrations (2.12 wt%, 6.97 wt%, and 10.53 wt%) on the annealing behavior ($750^{\circ}C$) of Ni-P samples and Cr double layered electrodeposits. Annealing temperature was simulated by combustion test condition. Also, we conducted SEM/EDS and XRD analysis for Ni-P/Cr samples. The results showed that the band layers between Ni-P and Cr are Ni and Cr, and has no formed with heat treatment. These band layers were solid solution of Cr and Ni which is formed by interdiffusion of both alloy elements. In addition, the P was not found in it. The thickness of band layer was increased with increasing annealing time. We expected that the band layer can improve the adhesion between Cr and Ni-P.

• 공업화학
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• 제10권3호
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• pp.336-342
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• 1999

탄소섬유 복합재료의 계면강도 증가를 위하여 탄소섬유의 표면처리에 대한 많은 연구가 이루어져 왔다. 기존의 상업적인 표면처리의 경우 탄소 섬유 표면 산화처리 후 수분산성 에폭시계 유기화합물을 코팅 (사이징처리)하여 탄소섬유에 에폭시 기지와의 상용성과 취급 용이성을 부여하고 있다. 이러한 재료로 제조된 탄소섬유 복합재료는 높은 층간 전단 강도를 나타내나 충격강도는 다소 낮은 특성을 가지고 있다. 본 연구에서는 탄소섬유 표면 산화 처리 후 기존의 사이징 처리 대신에 반응성과 유연성이 있는 계면상 (interphase)을 도입하여 복합재료의 층간전단강도와 충격강도를 향상시키고자 하였다. 탄소섬유의 전기전도성을 이용하여 이온화가능하고 연성을 가진 고분자인 MVEMA (poly (methyl vinyl ether-co-maIeic anhydride))와 EMA (poly (ethylene-co-maleic anhydride))를 수용액상에서 탄소섬유 표면에 전착 시키는 방법을 사용하였다. 전착에 의해 MVEMA 또는 EMA가 $0.1{\sim}0.2{\mu}m$ 두께로 얇게 코팅된 탄소섬유, 상용의 탄소섬유, 사이징처리를 하지 않은 탄소섬유로 복합재료를 제조하여 물성을 비교 평가하였다. 계면상의 두께가 얇을수록 층간전단강도가 증가하였으며, 충격강도는 감소하였는데, 계면상의 최적두께는 $0.1{\mu}m$ 정도였다. MVEMA 계면상을 도입한 경우가 상업적으로 표면처리 한 경우보다 층간전단강도의 경우 약 20% 정도 증가하였고 Izod 충격강도의 경우 약 50% 정도 증가하였다. MVEMA 계면상을 도입한 경우 복합재료의 흡습률이 높았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.294-294
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• 2010

CdS는 $CuInSe_2$계, CdTe계 이종접합 태양전지의 junction partner로 많이 이용되어 왔다. CdS는 전극으로 쓰일 뿐만 아니라 빛을 투과시키는 창문층으로 사용되어 높은 변환 효율을 나타낸다. 이종접합 태양전지에서 창문층은 가시광 영역에서 광투과율이 높고, 전기적으로 비저항이 낮아야 에너지 손실 없이 태양광을 광흡수층까지 투과시킬 수 있다. CdS 박막은 CBD법(solution growth technique), 진공증착법(vacuum evaporation), 스퍼터법(sputtering), 스프레이 열분해법(spray pyrolysis), 전착법(electrodeposition)에 의해 제조되고, 그 중 용액성장법(solution growth technique)이라고도 불리는 CBD법(chemical bath deposition)을 이용하여 CdS 박막을 제조하였다. CBD법은 다른 방법에 비해 제조 과정이 비교적 간단할 뿐만 아니라 제조 단가가 저렴하고, 넓은 면적의 박막 제조가 가능하며 재현성도 우수하다는 장점이 있다. CdS 박막을 제조하기 위한 cadmuim 이온공급원으로는 $CdSO_4$를 사용하였고 sulfur 이온공급원으로는 $SC(NH_2)_2$를 사용하였다. CBD법에서 박막의 물성에 영향을 미칠 수 있는 요인인 sulfur 이온공급원과 cadmium 이온공급원의 비, 용액의 온도, pH를 변화시켜 CdS 박막을 제조하였다. 각각의 조건에 의해 제조된 CdS의 박막의 두께는 Tencor P-1을 이용하여 측정되었고, UV-Visible spectrometer를 이용하여 파장에 따른 광투과율을 측정하였다. CdS 박막의 결정 구조를 조사하기 위해 X선 회절분석(XRD ; X-ray diffraction)을 하였고, AFM(Atomic Force Microscope)으로 표면 특성을 관찰하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.104-105
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• 2014

마이크로 패턴된 Au 전극사이에 얼라인된 Tellurium (Te) 나노리본들이 의도한 모양과 배열방식을 가지고 리쏘그래피 패턴 전해증착 (Lithographically patterned nanowier electrodepositon, LPNE) 방법에 의해 4인치 Si wafer 배치로 합성되었다. 합성된 Te 나노리본은 수 센티미터의 길이를 가지고, 그 두께와 폭 역시 작업 전극으로 사용되는 Si wafer위에 증착된 Ni의 두께와 전해증착 시간에 의해 쉽게 제어될 수 있다. $3{\mu}m$의 간격을 갖는 Au 전극 사이에 얼라인된 두께 ~100nm의 Te 나노리본들은 전해증착에 의해 그 폭이 제어되었고, 각각의 다른 폭을 갖는 증착된 하나의 Te 나노리본들의 IV 및 FET 측정을 통하여 나노리본 폭의 변화에 따른 전기적 특성 (비저항, FET 이동도 및 FET 캐리어 농도)이 평가되었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.432-434
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• 2009

Metal nano-wire arrays on Cu-coated seed layers were fabricated by aqueous solution method using sulfate bath at room temperature. The seed layers were coated on Anodic aluminum oxide (AAO) bottom substrates by electrochemical deposition technique, length and diameter of metal nano-wires were dominated by controlling the deposition parameters, such as deposition potential and time, electrolyte temperature. Anodic aluminum oxide (AAO) was used as a template to prepare highly ordered Ni, Fe, Co and Cu multilayer magnetic nano-wire arrays. This template was fabricated with two-step anodizing method, using dissimilar solutions for Al anodizing. The pore of anodic aluminum oxide templates were perfectly hexagonal arranged pore domains. The ordered Ni, Fe, Co and Cu systems nano-wire arrays were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Vibrating Sample Magnetometer (VSM). The ordered Ni, Fe, Co and Cu systems nano-wires had different preferred orientation. In addition, these nano-wires showed different magnetization properties under the electrodepositing conditions.