• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.79-79
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• 2005

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.243-250
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• 2018

Zinc oxide (ZnO) nanorods were grown on a palladium (Pd) activated polyacrylonitrile (PAN) fiber where Pd activation was carried out in advance by the following dry process: palladium(II) bis(acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into the surface of PAN fiber and spontaneously reduced to Pd nanoparticles at $180^{\circ}C$ for various times under a nitrogen atmosphere. ZnO nanorod morphology was observed by a scanning electron microscopy (SEM) and the elemental composition was confirmed by energy-dispersive X-ray spectroscopy (EDS). The crystalline structure of ZnO nanorods was analyzed by X-ray diffraction (XRD) analysis showing Wurtzite structure consisting of hexagonal lattice. Sulfur removal characteristics were evaluated.

• Korean Journal of Crystallography
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• v.17 no.1
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• pp.14-18
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• 2006

MOCVD 공정방법에 의해 수직정렬된 ZnO 나노선을 합성하고 공정조건 제어에 의해 합성되는 나노선의 물리적, 광학적 특성이 어떻게 변화하는지를 고찰하고자 하였다. 온도 및 산소분압제어 등의 공전변수 제어를 통하여 ZnO 나노 구조체는 나노선, 나노로드 뿐만 아니라 나노바늘 (nano-needle) 등 다양한 구조로 변화되었으며 그 직경 및 길이도 제어가 가능하였다. 전체적으로 양호한 특성의 wurzite 구조를 나타내었으며 기판에 수직인 방향으로 [0001] 방향으로 성장하였다. 광학특성에서는 나노선 직경이 작아질수록 주방출 피크의 천이현상이 관찰되었다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.482-484
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• 2008

Anodic aluminum oxide (AAO) which prepared with two-step anodizing method (with dissimilar solutions) was used as a template to fabricate highly ordered, free standing metal nano-rods. AAO nano-template technique can realize self-organized hexagonal pore structure with nanometer dimension size, it's easy to control pore diameter, length and density by varying anodizing conditions. Ni and Ni/Fe/Cu multi-metal layer nanorods were electrochemically deposited into AAO nano-template by AC voltage in simple sulfate solutions.. The properties of samples are tested by X-ray diffraction (XRD), field emission microscopy (FE-SEM).

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.617-621
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• 2009

Zinc oxide (ZnO) nanorods were grown on the pre-oxidized silicon substrate with the assistance of Au and the fluorine-doped tin oxide (FTO) based on the catalysts by vapor-liquid-solid (VLS) synthesis. Two types of ZnO powder particle size, 20nm, $20{\mu}m$, were used as a source material, respectively The properties of the nanorods such as morphological characteristics, chemical composition and crystalline properties were examined by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field-emission scanning electron microscope (FE-SEM). The particle size of ZnO source strongly affected the growth of ZnO nanostructures as well as the crystallographic structure. All the ZnO nanostructures are hexagonal and single crystal in nature. It is found that $1030^{\circ}C$ is a suitable optimum growth temperature and 20 nm is a optimum ZnO powder particle size. Nanorods were fabricated on the FTO deposition with large electronegativity and we found that the electric potential of nanorods rises as the ratio of current rises, there is direct relationship with the catalysts, Therefore, it was considered that Sn can be the alternative material of Au in the formation of ZnO nanostructures.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.5
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• pp.373-381
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• 2017

$RuO_2$ is a common active component of Dimensionally Stable Anodes (DSAs) for chlorine evolution that can be used in wastewater treatment systems. The recent improvement of chlorine evolution using nanostructures of $RuO_2$ electrodes to increase the treatment efficiency and reduce the energy consumption of this process has received much attention. In this study, $RuO_2$ nanorod and nanosheet electrodes were simply fabricated using the sol-gel method with organic surfactants as the templates. The obtained $RuO_2$ nanorod and nanosheet electrodes exhibit enhanced electrocatalytic activities for chlorine evolution possibly due to the active surface areas, especially the outer active surface areas, which are attributed to the increase in mass transfers compared with a conventional nanograin electrode. The electrocatalytic activities for chlorine evolution were increased up to 20 % in the case of the nanorod electrode and 35% in the case of the nanosheet electrode compared with the nanograin electrode. The $RuO_2$ nanorod 80 nm in length and 20-30 nm in width and the $RuO_2$ nanosheet 40-60 nm in length and 40 nm in width are formed on the surface of Ti substrates. These results support that the templated $RuO_2$ nanorod and nanosheet electrodes are promising anode materials for chlorine evolution in future applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.223.1-223.1
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• 2015

본 연구에서는 지름이 다른 두 개의 디스크가 적층된 구조를 갖는 금 나노 구조체를 제작하고 그 광학적 특성에 대해 연구하였다. 나노임프린팅을 통하여 패턴된 폴리머 포어 어레이에 금 박막을 증착하고, 포어 내부에 증착된 금 나노구조체를 선택적으로 수거하는 방법을 이용하였다 [1]. 특히 금 증착 시, 빗각으로 증착 (oblique-angle deposition)을 하여 지름이 다른 두 개의 디스크가 적층되어 있는 구조를 형성하는 것이 가능하였다. 증착 각도의 조절을 통해 적층된 두 디스크의 지름 비율을 변화시킬 뿐만 아니라, 2차원 디스크 형태의 나노구조체부터 3차원 디쉬 형태의 구조체도 제작이 가능함을 확인하였다. 제안된 하향식 나노공정을 통하여 합성된 금 나노구조체를 이용하여 광열 전환(photothermal heat conversion)과 광 간섭성 단층 (optical coherence tomography) 측정을 진행하였고, 서로 다른 두 개의 디스크가 적층된 형태의 금 나노구조체는 상용 금 나노로드 (Au nanorod) 보다 높은 광 열 전환 효율을 갖을 뿐 아니라 우수한 OCT 이미징 특성을 보였다. 광열 전환 및 OCT 이미징 실험 결과는 각각 플라즈모닉 나노구조의 광흡수, 광산란 특성에 기반하므로, 본 연구를 통하여 제안된 금 나노구조체는 광흡수 및 광산란을 기반한 바이오이미징 나노프로브로 유용하게 사용될 수 있을 것으로 전망된다.

• Clean Technology
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• v.20 no.3
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• pp.306-313
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• 2014

Nanoporous $TiO_2$ films are commonly used as working electrodes in dye-sensitized solar cells (DSSCs). So far, there have been attempts to synthesize films with various $TiO_2$ nanostructures to increase the power-conversion efficiency. In this work, vertically aligned rutile $TiO_2$ nanorods were grown on fluorinated tin oxide (FTO) glass by hydrothermal synthesis, followed by deposition of an anatase $TiO_2$ film. This new method of anatase $TiO_2$ growth avoided the use of a seed layer that is usually required in hydrothermal synthesis of $TiO_2$ electrodes. The dense anatase $TiO_2$ layer was designed to behave as the electron-generating layer, while the less dense rutile nanorods acted as electron-transfer pathwaysto the FTO glass. In order to facilitate the electron transfer, the rutile phase nanorods were treated with a $TiCl_4$ solution so that the nanorods were coated with the anatase $TiO_2$ film after heat treatment. Compared to the electrode consisting of only rutile $TiO_2$, the power-conversion efficiency of the rutile-anatase hybrid $TiO_2$ electrode was found to be much higher. The total thickness of the rutile-anatase hybrid $TiO_2$ structures were around $4.5-5.0{\mu}m$, and the highest power efficiency of the cell assembled with the structured $TiO_2$ electrode was around 3.94%.

• Journal of the Korean Vacuum Society
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• v.19 no.4
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• pp.293-299
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• 2010

Vertically aligned ZnO nanorods on Si (111) substrate were prepared by hydrothermal method. The ZnO nanorods on spin-coated seed layer were synthesized at $140^{\circ}C$ for 6 hours in autoclave and were thermally annealed in argon atmosphere for 20 minutes at temperature of 300, 500, $700^{\circ}C$. The effects of the thermal annealing on the structural and optical properties of the grown on ZnO nanorods were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL). All the ZnO nanorods show a strong ZnO (002) and weak (004) diffraction peak, indicating c-axis preferred orientation. The residual stress of the ZnO nanorods is changed from compressive to tensile by increasing annealing temperature. The hexagonal shaped ZnO nanorods are observed. The PL spectra of the ZnO nanorods show a sharp near-band-edge emission (NBE) at 3.2 eV, which is generated by the free-exciton recombination and a broad deep-level emission (DLE) at about 2.12~1.96 eV, which is caused by the defects in the ZnO nanorods. The intensity of the NBE peak is decreased and the DLE peak is red-shifted due to oxygen-related defects by thermal annealing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.541-548
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• 2015

We study the structural and functional characteristics of zinc oxide (ZnO) nanostructures that are grown on carbon nanotube (CNT) constructs via step-wise chemical vapor deposition (CVD). First, we optimize the CVD process to directly grow ZnO nanostructures on CNTs by controlling the growth temperature below $600^{\circ}C$, where CNTs can be sustained in a ZnO-growing oxidative atmosphere. We then investigate how the morphology and areal density of ZnO nanostructures evolve depending on process parameters, such as pressure, temperature, and gas feeding composition, while focusing on the effect of underlying CNT topology on ZnO nucleation and growth. Because various types of ZnO nanostructures, including nanowires, nanorods, nanoplates, and polycrystalline nanocrystals, can be conformally formed on highly conductive CNT platforms, this electrically addressable three-dimensional hybrid nanoarchitecture may better meet a wide range of nanoelectronic application-specific needs.