• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.7.1-7.1
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• 2011

Nanoporous templates have been widely used for the development of new functional nanostructured materials suitable for electronics, optics, magnetism, and energy storage materials. We have prepared nanoporous templates by using thin films of mixtures of polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) and PMMA homopolymers. These templates have cylindrical nanoholes spanning the entire thickness of the film. Some applications of nanoporous templates are introduced: a) anti-reflective coating, b) the preparation of conducting polymer nanowires of poly (pyrrole), poly (3,4-ethylenedioxy-thiopene) onto a glass coated with indium-tin-oxide, and c) the separation membranes for biomaterials. We found that when the pore fraction of nanoholes in the film was ~0.68, almost zero reflectance at a specific wavelength, which can be changed with film thickness, was achieved at visible wavelengths Furthermore, ultra high density array of conducting nanowires was successfully prepared onto various substrates including flexible polymer. Due to highly alignment of polymer chain along the nanowire direction, the conductivity was much increased. Furthermore, these nanoporous films were found to be very effective for the separation of human Rhinovirus type 14 (HRV 14), major pathogen of a common cold in humans, from the buffer solution. We also found that when the pore size was effectively controlled down to 6 nm, a single file diffusion was observed.

• KEPCO Journal on Electric Power and Energy
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• 제2권1호
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• pp.97-101
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• 2016

산화아연은 다양한 나노 구조와 특유의 특성으로 인하여 여러 분야에서 많은 관심을 받고있는 물질이다. 산화아연을 합성하는 다양한 방법 중에서, 수열합성법은 간단하고 친환경적인 장점을 가지고 있다. 나노 구조를 가지는 산화아연 박막은 수열합성법을 통하여 FTO 전극 위에 제작되었다. 성장된 산화아연은 X-ray diffraction (XRD)와 Field-emission scanning electron microscopy (FESEM)을 통하여 분석되었다. XRD 분석에서 산화아연 박막이 자연상태의 hexagonal wurtzite 상으로 구성되어 있음을 확인하였으며 SEM 사진에서는 나노 로드 형태를 구성하고 있는 것을 확인할 수 있었다. 본 연구에서는 UV 영역의 흡수 스펙트럼을 분석하여 산화아연이 보이는 365 nm 파장에서의 흡수를 확인하였다. 또한 photoluminescence 방출을 분석한 결과, 424 nm의 band edge emission과 500 nm에서 산화아연의 oxygen vacancies에 의한 방출을 확인하였다. 또한 라만 스펙트럼 분석을 통하여 본 연구진이 제작한 산화아연이 높은 결정성을 가지고 있는 것을 확인할 수 있었다. 이러한 연구를 통하여 다양한 특성을 가진 산화아연의 광촉매적 적용을 기대할 수 있다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.1.1-1.1
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• 2011

Electrospinning has known to be very effective tool for production of versatile one-dimensional (1D) nanostructured materials such as nanofibers, nanorod, and nanotubes and for easily assembly to two-, three-dimensional(2D, 3D) nanostructures such as thin film, membrane, and nonwoven web, etc. We have studied on the electrospinning technology for novel energy storage and conversion materials such as advanced separator, dye sensitized solar cell, supercapacitor, etc. High heat-resistive nanofibrous membrane as a new separator for future lithium ion polymer battery was prepared by electrospinning of PVdF based composite solution. The novel nanofibrous composite nonwovens have tensile strength of above 50 MPa and modulus of above 1.3 GPa. The internal structure of the electrospun composite nanofiber with a diameter of few hundreds nanometer were composed of core-shell nanostructure. And also electrospun $TiO_2$ nanorod/nanosphere based dye-sensitized solar cells with high efficiency are successfully prepared. Some battery performance will be introduced.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.45.2-45.2
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• 2010

Possessing of carbon nanotubes in biopolymer intrigued much interest due to their mechanical and unique nanoscale surface properties. Surface stiffness can be controlled by the amount of carbon nanotubes in polymer and surface wettability can be altered by the order of nanoscale surface roughness. Protein adsorption mechanism on nanostructured carbon nanotube/polymer thin film will be discussed in this study. In addition, we identified that mechanical stimuli also contribute the messenchymal stem cell and bone cell interactions. Importantly, live cell analysis system also showed altered morphology and cellular functions. Thus, embedding of carbon nanostructures simultaneously contribute to protein adsorption and cellular interactions. In conclusion, this study demonstrated the evidence that nanoscale surface features determine the subsequent biological interactions, such as protein adsorption and cellular interactions.

• 센서학회지
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• 제18권2호
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• pp.135-138
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• 2009

$64{\times}1$ forcal plane infrared detector has been fabricated by using HgCdTe epi layer. HgCdTe was grown on GaAs substrate by using metal organic chemical vapor deposition. This paper describes key developments in the epi layer growth and device fabrication process. The performance of IR imaging system is summarized.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.478-483
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• 2005

In this paper, we synthesized 10 to 20 nm diameter NiFe nanoparticles and nanoparticle films utilizing supersonic jet deposition of nanoparticle aerosols generated by laser ablation of $30\;to\;45{\mu}m$ diameter permalloy $(Ni_{81}Fe_{19} \;at\;{\%})$ microparticles. The component and composition of the nanoparticles were characterized by an energy dispersive X-ray spectroscopy. The morphology of the nanoparticles and nanoparticle films was analyzed by a high-resolution transmission electron microscopy and a scanning electron microscopy, respectively. The experimental results showed that the nanoparticles and nanoparticle films have remarkable properties with an excellent preservation of the composition of feedstock permalloy microparticles. The purpose of the present work is to present details on the composition and nanostructural characterizations for NiFe nanoparticles and nanoparticle films prepared by laser ablation of microparticles (LAM).

• Current Applied Physics
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• 제18권11호
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• pp.1399-1402
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• 2018

Nanorod films of cobalt oxide ($Co_3O_4$) have been grown by a unique oblique angle deposition (OAD) technique in an e-beam evaporator for supercapacitor electrode applications. This technique offers a non-chemical route to achieve large aspect ratio nanorods. The fabricated electrodes at OAD $80^{\circ}$ exhibited a specific capacitance of 2875 F/g. The electrochemically active surface area was $1397cm^{-2}$, estimated from the non-Faradaic capacitive current region. Peak energy and power densities obtained for $Co_3O_4$ nanorods were 57.7 Wh/Kg and 9.5 kW/kg, respectively. The $Co_3O_4$ nanorod electrode showed a good endurance of 2000 charge-discharge cycles with 62% retention. The OAD approach for fabricating supercapacitor nanostructured electrodes can be exploited for the fabrication of a broad range of metal oxide materials.

• 한국표면공학회지
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• 제53권6호
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• pp.343-350
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• 2020

The degradation of mechanical properties of nitride coatings to steel substrates is one of the main challenges for industrial applications. In this study, plasma nitriding treatment was used in order to increase the mechanical properties of Mo-Cu-N coating to the H13 tool steel. The nanostructured Mo-Cu-N coating was deposited using pulsed DC magnetron sputtering method with a single alloy Mo-Cu target. Mechanical properties of MoN-Cu coated samples after nitriding were found to be relatively better than non-nitrided MoN-Cu coating.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.13-15
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• 2005

The growth of $Bi_2Te_3$ thin films on (001) GaAs substrates by metal organic chemical vapour deposition (MOCVD) is discussed in this paper. The results of surface morphology, electrical and thermoelectrical properties as a function of growth parameters are given. The surface morphologies of $Bi_2Te_3$ films were strong1y dependent on the deposition temperatures. Surface morphologies varied from step-flow growth mode to island coalescence structures depending on deposition temperature. In-plane carrier concentration and electrical Hall mobility were highly dependent on precursor's ratio of Te/Bi and deposition temperature. The high Seebeck coefficient (of $-160{\mu}VK^{-1}$) and good surface morphology of our result is promising for $Bi_2Te_3$ based thermoelectric thin film and two dimensional supperlattice device applications.

• Journal of Electrochemical Science and Technology
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• 제7권4호
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• pp.277-285
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• 2016

There is a growing demand for simple, cost-effective, and accurate analytical tools to determine the concentrations of biological and environmental compounds. In this study, a stable electroactive thin film of cobalt hexacyanoferrate (Cohcf) was prepared as an in situ chemical precipitant using electrostatic adsorption of $Co^{2+}$ on a silicate sol-gel matrix (SSG)-modified indium tin oxide electrode pre-adsorbed with $[Fe(CN)_6]^{3-}$ ions. The modified electrode was characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical techniques. Electrocatalytic oxidation of hydrazine on the modified electrode was studied. An electrochemical sensor for hydrazine was constructed on the SSG-Cohcf-modified electrode. The oxidation peak currents showed a linear relationship with the hydrazine concentration. This study provides insight into the in situ growth and stability behavior of Cohcf nanostructures and has implications for the design and development of advanced electrode materials for fuel cells and sensor applications.