• Journal of the Korean Vacuum Society
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• v.22 no.4
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• pp.204-210
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• 2013

In order to improve osseointegration for biomedical implants, it is crucial to understand the interactions between nanostructured surfaces and cells. In this study, $TiO_2$ nanowires were prepared via Vapor-Liquid-Solid (VLS) process with Sn as a metal catalyst in the tube furnace. Nanowires were grown with $N_2$ heat treatment with their size controlled by the agglomeration of Sn layers in various thicknesses. MC3T3-E1 (pre-osteoblast) were cultured on the $TiO_2$ nanowires for a week. Preliminary results of the cell culture showed that the cells adhere well on the $TiO_2$ nanowires.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.323-324
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• 2023

The properties of cement mortar mixed with manganese-doped titanium dioxide nanowires (TiO₂(Mn)-NWs) were investigated in this study. The TiO₂(Mn)-NWs were synthesized using solvo-thermal synthesis and electro-spinning techniques. The TiO₂(Mn)-NWs at weights of 1%, ₂%, and 3% of the cement were respectively mixed into the cement mortar. The results showed that as the amount of TiO₂(Mn)-NWs increased, the flow value of the cement mortar was decreased and the setting time of cement mortar was accelerated. Moreover, as the amount of TiO₂(Mn)-NWs increased, the compressive strength of cement mortar was increased and the efficiency of acetaldehyde removal was improved.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.123-128
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• 2017

Nanostructured materials have received attention due to their unique electronic, optical, optoelectrical, and magnetic properties as a results of their large surface-to-volume ratio and quantum confinement effects. Thermal chemical vapor deposition process has attracted much attention due to the synthesis capability of various structured nanomaterials during the growth of nanostructures. In this study, silicon oxide nanowires were grown on Si\$SiO_2$(300 nm)\Pt(5~40 nm) substrates by two-zone thermal chemical vapor deposition with the source material $TiO_2$ powder via vapor-liquid-solid process. The morphology and crystallographic properties of the grown silicon oxide nanowires were characterized by field-emission scanning electron microscope and transmission electron microscope. As results of analysis, the morphology, diameter and length, of the grown silicon oxide nanowires are depend on the thickness of the catalyst films. The grown silicon oxide nanowires exhibit amorphous phase.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.35.1-35.1
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• 2011

수열합성법으로 제작된 ZnO 나노와이어는 저온 MBE (Molecular Beam Epitaxy) 방식과 달리 Ti, Au와 같은 촉매로 부터 성장이 끝난뒤 나노와이어 끝에 남는 촉매를 제거해야할 필요가 없으며, 저온에서 합성이 가능하기 때문에 현재 연구가 많이 되고 있는 방법중에 하나이다. 본 연구에서는 수열 합성법을 이용하여 금속촉매 또는 AZO로 seed를 형성한 후 기판 위에 균일한 크기의 ZnO 나노막대를 성장시키고 성장밀도 및 길이의 간편한 제어를 하였다. 이를 위해 계면활성제인 PEI (Polyethyleneimine) 첨가 및 Chloride ($Cl_-$)를 조절하여 ZnO 나노와어의 성장밀도를 조절 하고자 하였다. 실험방법으로는 전구체인 Zn(NO3)2${\cdot}$6H2O와 HMT에 Chloride 계열인 Ammonium chloride 와 Kcl 의 몰농도를 각각 조절하고 PEI를 첨가하여, ZnO 나노와이어를 성장하였다. 성장된 ZnO 나노와이어의 특성을 평가하기 위해 field emission scanning electron microscopy (FE-SEM)을 이용하여 광학적인 특성을 측정하였으며, 결정성을 조사하기 위해 X-ray diffraction (XRD)을 이용하여 분석하였다. 또한 scanning PL 장비를 통해 photoluminescence양을 측정하고 ZnO 나노와이어의 응용 가능성을 평가하였다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.118-119
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• 2021

The properties of cement mortar with graphene-titanium dioxide composite nanowires (TiO2(G)NW) were investigated in this study. The following tests were conducted with the cement mortar : (1) setting times (2) Flow test of fresh cement mortar, (3) compressive strength and (4) acetaldehyde removal efficiency under visible light. As the increase of TiO2(G) NW, the flow value of cement mortar was decreased and the setting times of cement mortar were faster. The compressive strength and the acetaldehyde removal efficiency were increased by the increase of TiO2(G) NW.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.1
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• pp.1-8
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• 2017

Catalytic synthesis and properties of ${\beta}-Ga_2O_3$ nanowires grown by metal organic chemical vapor deposition are reported. Au, Ni and Cu catalysts were suitable for the growth of $Ga_2O_3$ nanowires under our experimental conditions. The $Ga_2O_3$ nanowires grown by using Au, Ni and Cu catalysts showed different growth rates and morphologies in each case. We found the $Ga_2O_3$ nanowires were grown by the Vapor-Solid (VS) process when Ni was used as a catalyst while the Vapor-Liquid-Solid (VLS) was a dominant process in case of Au and Cu catalysts. Also, we found nanowires showed different optical properties depend on catalytic metals. On the other hand, for the cases of Ti, Sn and Ag catalysts, nanowires could not be obtained under the same condition of Au, Cu and Ni catalytic synthesis. We found that these results are related to the different characteristics of each catalyst, such as, melting points and phase diagrams with gallium metal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.432-432
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• 2009

본 연구에서는 HW-PLD(Hot-walled Pulsed Laser Deposition) 법을 이용하여 ZnO 나노와이어를 $Al_2O_3$ 기판 위에 성장하였다. 성장된 ZnO 나노와이어는 SEM, XRD, PL 분석을 통하여 구조적 특성을 확인하였으며, 성장된 나노와이어를 photolithography 공정을 통하여 FET(Field Effect Transistor)소자를 제작하였다. 제작된 소자의 I-V 특성 측정 결과 Ti/Au 전극과 ZnO nanowire 채널 간에 ohmic 접합이 형성된 것을 확인하였으며 게이트 전압의 증가에 따라 소스와 드레인 사이의 전류가 증가하는 전형적인 n-type FET소자 특성을 나타내었다.

• Journal of the Korean institute of surface engineering
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• v.48 no.5
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• pp.238-244
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• 2015

$TiO_2$ nanowires were synthesized by hydrothermal method for the application to ethanol gas sensor. $TiO_2$ nanowires were decorated with Au nanoparticles to improve the sensitivity to ethanol gas. Scanning electron microscopy and Transmission electron microscopy revealed that the synthesized nanowires had diameters and lengths of approximately 100 - 200 nm and a few micrometers, respectively. Size of the Au nanoparticles decorated on the $TiO_2$ nanowires was observed to be in the range of 10 - 20 nm. X-ray diffraction confirmed that the decorated nanowires were composed of anatase-, rutile-$TiO_2$, and Au. The sensitivities of $TiO_2$ nanowires sensors decorated with Au were approximately 1.1 - 3.65 times as high as those of as-synthesized $TiO_2$ sensors for the ethanol concentration of 5 - 100 ppm at $200^{\circ}C$. The mechanism of the improved ethanol gas sensing of the $TiO_2$ nanowires decorated with Au nanoparticles is discussed.

• Journal of Powder Materials
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• v.25 no.1
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• pp.48-53
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• 2018

One-dimensional rutile $TiO_2$ is an important inorganic compound with applicability in sensors, solar cells, and Li-based batteries. However, conventional synthesis methods for $TiO_2$ nanowires are complicated and entail risks of environmental contamination. In this work, we report the growth of $TiO_2$ nanowires on a Ti alloy powder (Ti-6wt%Al-4wt%V, Ti64) using simple thermal oxidation under a limited supply of $O_2$. The optimum condition for $TiO_2$ nanowire synthesis is studied for variables including temperature, time, and pressure. $TiO_2$ nanowires of ${\sim}5{\mu}m$ in length and 100 nm in thickness are richly synthesized under the optimum condition with single-crystalline rutile phases. The formation of $TiO_2$ nanowires is greatly influenced by synthesis temperature and pressure. The synthesized $TiO_2$ nanowires are characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HR-TEM).

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.94-98
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• 2020

The core/shell of nanowires (NWs) with Cu-doped CdSe quantum dots were fabricated as an electron transport layer (ETL) for perovskite solar cells, based on ZnO/TiO2 arrays. We presented CdSe with Cu2+ dopants that were synthesized by a colloidal process. An improvement of the recombination barrier, due to shell supplementation with Cu-doped CdSe quantum dots. The enhanced cell steady state was attributable to TiO2 with Cu-doped CdSe QD supplementation. The mechanism of the recombination and electron transport in the perovskite solar cells becoming the basis of ZnO/TiO2 arrays was investigated to represent the merit of core/shell as an electron transport layer in effective devices.