• 공업화학
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• 제27권4호
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• pp.421-426
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• 2016

본 연구에서는 폴리옥소메탈레이트(polyoxometalate, POM)가 도핑된 폴리피롤(polypyrrole, Ppy)을 3차원 구조의 탄소천(carbon cloth, CC) 표면 위에 전기화학적 증착법을 이용하여 합성하고 이의 의사커패시터 특성을 순환전압전류법과 정전류 충전-방전법을 사용하여 분석하였다. POM-Ppy의 코팅은 전기화학적 증착 시간에 따라서 얇은 conformal형태의 코팅으로 조절되었다. 제조된 POM-Ppy/CC의 재료 특성은 전자주사현미경과 X-선 분광분석을 사용하여 분석하였다. POM-Ppy/CC의 3차원 나노복합체 구조는 높은 비정전용량($561mF/cm^2$), 고속 충방전(85% 용량 유지율) 및 장수명 특성(97% 용량 유지율)을 나타내었다.

• 한국재료학회지
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• 제14권9호
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• pp.619-626
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• 2004

Pulsed metalorganic chemical vapor deposition (MOCVD) of conformal copper seed layers, for the electrodeposition Cu films, has been achieved by an alternating supply of a Cu(I) source and $H_2$ reactant at the deposition temperatures from 50 to $100^{\circ}C$. The Cu thickness increased proportionally to the number of cycles, and the growth rate was in the range from 3.5 to $8.2{\AA}/cycle$, showing the ability to control the nano-scale thickness. As-deposited films show highly smooth surfaces even for films thicker than 100 nm. In addition about a $90\%$ step coverage was obtained inside trenches, with an aspect ratio greater than 30:1. $H_2$, introduced as a reactant gas, can play an active role in achieving highly conformal coating, with increased grain sizes.

• 대한전자공학회논문지TC
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• 제41권12호
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• pp.131-137
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• 2004

본 논문에서는 등각사상 법을 이용해 유전체가 다층으로 코팅된 평행 2선식 전송선로의 특성임피던스 및 유효 유전상수 등을 계산하는 방법을 제안하였다. 먼저 두께 및 유전상수가 다른 유전체가 임의의 N 층으로 코팅되었을 때 평행 2선식 전송선로의 정전용량을 계산하였으며, 이를 이용해 임피던스 및 유효 유전상수 등을 계산하였다. Ansoft 사의 Maxwell 2D를 이용한 시뮬레이션 결과와 비교하였을 때, 계산 결과가 오차범위 4% 이내로 거의 일치함을 알 수 있었다.

• 센서학회지
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• 제32권6호
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• pp.335-339
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• 2023

Skin-compatible electronics have evolved to achieve both conformality and stretchability for stable contact with deformable biological skin. While existing research has largely concentrated on alternative materials, the potential of Parylene-based thin-film electrodes for stretchable on-skin applications remains relatively untapped. This study proposes an engineering strategy to achieve stretchability using the Parylene thin-film electrode. Unlike the conventional Parylene thin-film electrode, we introduce morphological adaptability via controlled microscale slits in the Parylene electrode structure. The slits-containing device enables unprecedented stretchability while maintaining critical electrical insulation properties during mechanical deformation. Finally, the demonstration on human skin shows the mechanical adaptability of these Parylene-based bioelectrodes while their electrical characteristics remain stable during various stretching conditions. Owing to the ultra-thinness of the Parylene coating, the wearable bioelectrode not only achieves stretchability but also conforms to the skin. Our findings broaden the practical use of Parylene thin-film bioelectrodes.

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.196-205
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• 2019

Ni-rich layered oxides $Li(Ni_xCo_yMn_z)O_2$ (x + y + z = 1) have been extensively studied in recent times owing to their high capacity and low cost and can possibly replace $LiCoO_2$ in the near future. However, these layered oxides suffer from problems related to the capacity fading, thermal stability, and safety at high voltages. In this study, we use surface coating as a strategy to improve the thermal stability at higher voltages. The uniform and conformal $Al_2O_3$ coating on prefabricated electrodes using atomic layer deposition significantly prevented surface degradation over prolonged cycling. Initial capacity of 190, 199, 188 and $166mAh\;g^{-1}$ is obtained for pristine, 2, 5 and 10 cycles of ALD coated samples at 0.2C and maintains 145, 158, 151 and $130mAh\;g^{-1}$ for high current rate of 2C in room temperature. The two-cycle $Al_2O_3$ modified cathode retained 75% of its capacity after 500 cycles at 5C with 0.05% capacity decay per cycle, compared with 46.5% retention for a pristine electrode, at an elevated temperature. Despite the insulating nature of the $Al_2O_3$ coating, a thin layer is sufficient to improve the capacity retention at a high temperature. The $Al_2O_3$ coating can prevent the detrimental surface reactions at a high temperature. Thus, the morphology of the active material is well-maintained even after extensive cycling, whereas the bare electrode undergoes severe degradation.

• 한국표면공학회지
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• 제31권1호
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• pp.34-44
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• 1998

Stainless steel is being used widely lor various purposes due to its good corrosion resistance. There has becn much research to produce colored stainless sterl by several methods. In this experiment, we coated TixN film on the SUS304 substrate with thc DC magnetron sputtering system and studied the internal structurc and adhesive strength of the films as a function of the coating conditions. Before lhe specimen was coated, a sputter etching was very effective in removing the$\delta$ Fe(BCC) phase as well as the contaminant and oxide layer as well as increasing rotghness. Five-stage failure mode appeared with increased scratch load with the TIN films coated on the SUS304 in this manner ; tensile failure-,conformal failure-,buckling failure->chipping failurc and spalling Failure. When the failure was terminated at the initial stage, the film will have good adhesion. But, if syalling failure has occurred at the initial scratch, then the adhesion will be poor. The interlayer between thc coated film and thc substratc was homogeneously adhcsive when the $\gamma'-Fe_4N$ phase wasn't detected in the XRD analysis and the adhesive strength only was reduced by surPace defects. But, when the ,$\gamma'-Fe_4N$N phasc was detected in the XRD analysis, the adhesive strength was very poor.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.401-401
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• 2016

Although vertically aligned one-dimensional (1D) structure has been considered as efficient forms for photoelectrode, development of efficient 1D nanostructured photocathode are still required. In this sense, we recently demonstrated a simple fabrication route for CuInS2 (CIS) nanorod arrays from aqueous solution by template-assisted growth-and-transfer method and their feasibility as a photoelectrode for water splitting. In this study, we further evaluated the photoelectrochemical properties surface-modified CIS nanorod arrays. Surface modification with CdS and ZnS was performed by successive ion layer adsorption and reaction (SILAR) method, which is well known as suitable technique for conformal coating throughout nanoporous structure. With surface modification of CdS and ZnS, both photoelectrochemical performance and stability of CuInS2 nanorod arrays were improved by shifting of the flat-band potential, which was analyzed both onset potential and Mott-schottky plot.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권2호
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• pp.66-69
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• 2003

Various semiconductor nanowires such as GaN, GaP, InP, Si$_3$N$_4$, SiO$_2$/Si, and SiC were coated conformally with aluminum oxide (Al$_2$O$_3$) layers by atomic layer deposition (ALD) using trimethylaluminum (TMA) and distilled water ($H_2O$) at a temperature of 20$0^{\circ}C$. Transmission electron microscopy (TEM) revealed that A1203 cylindrical shells conformally coat the semiconductor nanowires. This study suggests that the ALD of $Al_2$O$_3$ on nanowires is a promising method for preparing cylindrical dielectric shells for coaxially gated nanowire field-effect transistors.

• Journal of Welding and Joining
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• 제31권3호
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• pp.22-30
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• 2013

Due to ELV banning, automotive electronics cannot use four kinds of heavy metal element (Pb, Hg, Cd, $Cr^{6+}$) from 2016. Therefore, this study was focused on degradation characteristics of Sn-3.0Ag-0.5Cu Lead-free solder joint with OSP and ENIG finsh under various reliability assessment method, as like to thermal shock test and high temeprature/high humidity test with test duration for cabin electronics. Also, we compared bonding strength degradation to other advanced research results of electronic control unit for engine room because of difference service temperature with mount location in automotive. Whisker growth phenomenon and mitigation method which were essentially consideration items for Pb-free car electronics were examined. Conformal coating is a strong candidate for mitigating whisker growth in automotive electronics. Necessary condition to adapt Pb-free in car electronics was shown.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.264.2-264.2
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• 2013

Molecular layer deposition (MLD) is sequential, self-limiting surface reaction to form conformal and ultrathin polymer film. This technique generally uses bifunctional precursors for stepwise sequential surface reaction and entirely organic polymer films. Also, in comparison with solution-based technique, because MLD is vapor-phase deposition based on ALD, it allows epitaxial growth of molecular layer on substrate and is especially good for surface reaction or coating of nanostructure such as nanopore, nanochannel, nanwire array and so on. In this study, polyurea film that consisted of phenylenediisocyanate and phenylenediamine was formed by MLD technique. In situ Fourier Transform Infrared (FTIR) measurement on high surface area SiO2 substrate was used to monitor the growth of polyurethane and polyurea film. Also, to investigate orientation of chemical bonding formed polymer film, plan-polarized grazing angle FTIR spectroscopy was used and it showed epitaxial growth and uniform orientation of chemical bones of polyurea films.