• Korean Journal of Materials Research
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• v.30 no.9
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• pp.441-446
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• 2020

Synthesizing nanostructured thin films of oxide semiconductors is a promising approach to fabricate highly efficient photoelectrodes for hydrogen production via photoelectrochemical (PEC) water splitting. In this work, we investigate the feasibility as an efficient photoanode for PEC water oxidation of zinc oxide (ZnO) nanostructured thin films synthesized via a simple method combined with sputtering Zn metallic films on a fluorine-doped tin oxide (FTO) coated glass substrate and subsequent thermal oxidation of the sputtered Zn metallic films in dry air. Characterization of the structural, optical, and PEC properties of the ZnO nanostructured thin film synthesized at varying Zn sputtering powers reveals that we can obtain an optimum ZnO nanostructured thin film as PEC photoanode at a sputtering power of 40 W. The photocurrent density and optimal photocurrent conversion efficiency for the optimum ZnO nanostructured thin film photoanode are found to be 0.1 mA/㎠ and 0.51 %, respectively, at a potential of 0.72 V vs. RHE. Our results illustrate that the ZnO nanostructured thin film has promising potential as an efficient photoanode for PEC water splitting.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1530-1533
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• 2005

We investigated under-gate type carbon nanotube field emitter arrays (FEAs) for back light unit (BLU) in liquid crystal display (LCD). Gate oxide was formed by wet etching of ITO coated glass substrate instead of depositing $SiO_2$ on the glass substrate. Wet etching is easer and simpler than depositing and etching of thick gate oxide to isolate the gate metal from cathode electrode in triode. Field emission characteristic s of triode structure were measured. The maximum current density of 92.5 ${\mu}A/cm^2$ was when the gate and anode voltage was 95 and 2500 V, respectively at the anode-cathode spacing of 1500 ${\mu}m$.

• Journal of Electrochemical Science and Technology
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• v.11 no.2
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• pp.99-116
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• 2020

The article provides information on ceramic / nanostructured materials which are suitable for solid oxide fuel cells (SOFCs) working between 500 to 1000℃. However, low temperature solid oxide fuel cells LTSOFCs working at less than 600℃ are being developed now-a-days with suitable new materials and are globally explored as the "future energy conversion devices". The LTSOFCs device has emerged as a novel technology especially for stationary power generation, portable and transportation applications. Operating SOFC at low temperature (i.e. < 600℃) with higher efficiency is a bigger challenge for the scientific community since in low temperature regions, the efficiency might be less and the components might have exhibited lower catalytic activity which may result in poor cell performance. Employing new and novel nanoscale ceramic materials and composites may improve the SOFC performance at low temperature ranges is most focused now-a-days. This review article focuses on the overview of various ceramic and nanostructured materials and components applicable for SOFC devices reported by different researchers across the globe. More importance is given for the nanostructured materials and components developed for LTSOFC technology so far.

• Proceedings of the Korean Vacuum Society Conference
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• 2002.06a
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• pp.130-130
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• 2002

• Proceedings of the Korean Vacuum Society Conference
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• 2004.02a
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• pp.111-111
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• 2004

• Nano
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• v.13 no.12
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• pp.1850143.1-1850143.9
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• 2018

Natural biotemplates - such as bacteria, fungi and viruses - are used in nanostructured metal oxide production. The pollen can be found abundantly in nature, and their microcapsules can be easily isolated from the pollen by chemical treatments. To date, pollen microcapsules are mostly used as drug carriers and catalytic agent templates. In the present study, nanoporous-structured nickel oxide is produced using Pistachio pollen microcapsules. The raw pollen, chemically treated pollen and metal-coated pollen were characterized using scanning electron microscopy, Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. The natural Pistachio pollen which were procured from Gaziantep, Turkey, are spherical, with a diameter of approximately $23{\mu}m$. The maximum surface area obtained for nickel oxide-coated microcapsules is $228.82m^2/g$. This result shows that Pistachio pollen are an excellent candidate for the production of porous nanostructured materials for supercapacitor electrodes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.3
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• pp.308-310
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• 2022

Ultrawide bandgap gallium oxide (Ga₂O₃) semiconductors are known to have excellent photocatalytic properties due to their high redox potential. In this study, CO₂ reduction is demonstrated using nanostructured Ga₂O₃ photocatalyst under ultraviolet (254 nm) light source conditions. After the CO₂ reduction, C₂H₄ remained as a by-product in this work. Nanostructured Ga₂O₃ photocatalyst also showed an excellent endurance characteristic. Photogenerated electron-hole pairs boosted the CO₂ reduction to C₂H₄ via nanostructured Ga₂O₃ photocatalyst, which is attributed to the ultrawide and almost direct bandgap characteristics of the gallium oxide semiconductor. The findings in this work could expedite the realization of CO₂ reduction and a simultaneous C₂H₄ production using a low cost and high performance photocatalyst.

• Proceedings of the Korean Vacuum Society Conference
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• 2002.06a
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• pp.111-111
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• 2002

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.697-700
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• 2002

Porous anodic aluminum oxide(AAO) templates prepared by anodizing method were used for growing multiwalled carbon nanotubes(CNTs). AAO templates with the homogeneous pore diameter and length were obtained by two step anodizing technique. Using AAO templates, vertically well-ordered two-dimensional carbon nanotube arrays were fabricated. We investigated the field emission property of CNTs grown using different catalyst metals in vacuum chamber (<$10^{-7}$ Torr) on AAO Template. To explain the different emission property, the surface reaction between catalysts and alumina pores which inserted carbon species of $C_2H_2$ using High resolution transmission electron microscopy (HRTEM) was studied.

• Journal of Powder Materials
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• v.13 no.3 s.56
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• pp.192-198
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• 2006

The nanostructured cerium oxide powders were synthesized by spray thermal decomposition process for the use as the raw materials of resistive oxygen sensor. The synthesis routes consisted of 1) spray drying of water based organic solution made from cerium nitrate hydrate ($Ce(NO_3){_3}6H_2O$) and 2) heat treatment of spray dried precursor powders at $400^{\circ}C$ in air atmosphere to remove the volatile components and identically to oxidize the cerium component. The produced powders have shown the loose structure agglomerated with extremely fine cerium oxide particles with about 15 nm and very high specific surface area ($110m^2/g$). The oxygen sensitivity, n ($Log{\propto}Log (P_{O2}/P^o)^{-n}$ and the response time, $t_{90}$ measured at $600^{\circ}C$ in the sample sintered at $1000^{\circ}C$, were about 0.25 and 3 seconds, respectively, which had much higher performances than those known in micron or $100{\sim}200nm$ sized sensors.