• Journal of Powder Materials
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• v.18 no.1
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• pp.49-55
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• 2011

Ni nanowires were fabricated using anodic aluminum oxide (AAO) membrane as a template by electrochemical deposition. The nanowires were formed within the walls of AAO template with 200 nm in pore diameter. After researching proper voltage and temperature for electrochemical deposition, the length of Ni nanowires was controlled by deposition time and the supply of electrolyte. The morphology and microstructure of Ni nanowires were investigated by field emission scanning electron microscope (FE-SE), X-ray diffraction (XRD) and transmission electron microscope (TEM).

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3571-3574
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• 2011

Nano-scaled metal oxides have been attractive materials for sensors, photocatalysis, and dye-sensitization for solar cells. We report the controlled synthesis and characterization of single crystalline $TiO_2$ nanowires via a catalyst-assisted vapor-liquid-solid (VLS) and vapor-solid (VS) growth mechanism during TiO powder evaporation. Scanning electron microscope (SEM) and transmission electron microscope (TEM) studies show that as grown $TiO_2$ materials are one-dimensional (1D) nano-structures with a single crystalline rutile phase. Also, energy-dispersive X-ray (EDX) spectroscopy indicates the presence of both Ti and O with a Ti/O atomic ratio of 1 to 2. Various morphologies of single crystalline $TiO_2$ nano-structures are realized by controlling the growth temperature and flow rate of carrier gas. Large amount of reactant evaporated at high temperature and high flow rate is crucial to the morphology change of $TiO_2$ nanowire.

• Journal of Magnetics
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• v.22 no.1
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• pp.100-103
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• 2017

We studied the microstructure and magnetic properties of Fe nanosized powder synthesized by the pulsed wire evaporation method. The x-ray diffraction spectrum confirmed that this powder had a pure ${\alpha}$-Fe phase. Scanning electron microscope and transmission electron microscope measurements indicated that the prepared powder had uniform spherical shape with core-shell structure. The mean powder size was about 35 nm and the thickness of the surface passivation layer was about 5 nm. Energy dispersive X-ray spectroscopy measurement indicated that the surface passivation layer was iron oxide. Magnetic field dependent magnetization measurement at room temperature showed that the maximum magnetization of the prepared powder was 177.1 emu/g at 1 T.

• Journal of the Korean Electrochemical Society
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• v.14 no.1
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• pp.22-26
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• 2011

Polypyrrole (Ppy) nanowire has been electrochemically synthesized via vertically oriented mesoporous silica template. The mesoporous template is also electrochemically deposited on indium tin oxide coated (ITO) glass from tetraethyl orthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) surfactant. The highly ordered silica template is demonstrated to be 100~120nm thick with the pores of 4~5 nm diameter by scanning electron microscope (SEM) and transmission electron microscope (TEM). Ppy is formed to fill pores of the silica template from pyrrole solution by electrochemical oxidation. The Ppy in Ppy/silica/ITO composite was found to exhibit reversible electrochemical activity, as characterized by cyclic voltammetry (CV).

• Applied Microscopy
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• v.39 no.1
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• pp.73-77
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• 2009

Contaminative artifacts such as carbonaceous materials on carbon-coated microgrids are unavoidable, which is induced by electron beam exposure inside electron microscopes. This phenomenon raise a source to produce confusing information to the samples investigated by analytical TEM, which should be alleviated as much as possible. As experimental precautions for reducing this unwanted effect, the use of $LN_2$ cooled anti-contaminator and pre-illumination of electron beam at low magnification can be helpful. Nevertheless, we should be cautious to set an illumination condition for microanalysis because the contaminative effect is dependent with the types of irradiation situations, which is well known to be a decisive factor for causing the carbonaceous artifacts. Accordingly, it is necessary that optimal illumination to minimize the contaminative effect should be selected for improving the accuracy of microanalysis. In this paper, we introduce the practical method to determine the optimal illumination condition by evaluating the contaminative effect as a function of instrumental spot size, which is directly linked with electron current density.

• Applied Microscopy
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• v.49
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• pp.3.1-3.7
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• 2019

Graphene, which is one of the most promising materials for its state-of-the-art applications, has received extensive attention because of its superior mechanical properties. However, there is little experimental evidence related to the mechanical properties of graphene at the atomic level because of the challenges associated with transferring atomically-thin two-dimensional (2D) materials onto microelectromechanical systems (MEMS) devices. In this study, we show successful dry transfer with a gel material of a stable, clean, and free-standing exfoliated graphene film onto a push-to-pull (PTP) device, which is a MEMS device used for uniaxial tensile testing in in situ transmission electron microscopy (TEM). Through the results of optical microscopy, Raman spectroscopy, and TEM, we demonstrate high quality exfoliated graphene on the PTP device. Finally, the stress-strain results corresponding to propagating cracks in folded graphene were simultaneously obtained during the tensile tests in TEM. The zigzag and armchair edges of graphene confirmed that the fracture occurred in association with the hexagonal lattice structure of graphene while the tensile testing. In the wake of the results, we envision the dedicated preparation and in situ TEM tensile experiments advance the understanding of the relationship between the mechanical properties and structural characteristics of 2D materials.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.2
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• pp.15-18
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• 2001

The Mo/si multilayer for EUV lithography was deposited using magnetron sputtering system. The multilayers were characterized using the cross-sectional transmission electron microscope (TEM) and low/high angle X-ray diffraction (XRD). The microstructure of Mo and Si was highly textured structure and amorphous, respectively. The well-defined low angle XRD peaks implies a well-defined multilayer structure. The interfacial layer of Mo-on-Si was thicker than Si-on-Mo interfacial layer.

• Transactions on Electrical and Electronic Materials
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• v.5 no.4
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• pp.143-147
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• 2004

Surface defects and bulk defects on SOI wafers are studied. Two new metrologies have been proposed to characterize surface and bulk defects in epitaxial layer transfer (ELTRAN) wafers. They included the following: i) laser scattering particle counter and coordinated atomic force microscopy (AFM) and Cu-decoration for defect isolation and ii) cross-sectional transmission electron microscope (TEM) foil preparation using focused ion beam (FIB) and TEM investigation for defect morphology observation. The size of defect is 7.29 urn by AFM analysis, the density of defect is 0.36 /cm$^2$ at as-direct surface oxide defect (DSOD), 2.52 /cm$^2$ at ox-DSOD. A hole was formed locally without either the silicon or the buried oxide layer (Square Defect) in surface defect. Most of surface defects in ELTRAN wafers originate from particle on the porous silicon.

• Applied Microscopy
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• v.27 no.3
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• pp.257-263
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• 1997

Microstructural characterizations of II-VI blue laser diodes which consist of quaternary $Zn_{1-x}Mg_xS_ySe_{l-y}$ cladding layer, ternary $ZnS_ySe_{l-y}$ guiding layer and $Zn_{0.8}Cd_{0.2}Se$ quantum well as active layer were carried out using the transmission electron microscope working at 300 kV. Even though the entire structure is pseudomorphic to GaAs substrate, the structure had contained numerous extended stacking faults and dislocations which had created at ZnSe/GaAs interfaces and then further grown to the top of the epilayers. These faults might be expected to cause the degradation and shortening the lifetime of laser devices.

• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.173-179
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• 2006

Due to the limitations of the channel length, the lateral spread for two-dimensional impurity distributions is critical for the analysis of devices including the integrated complementary metal oxide semiconductor (CMOS) circuits and high frequency semiconductor devices. The developed codes were then compared with the two-dimensional implanted profiles measured by transmission electron microscope (TEM) as well as simulated by a commercial TSUPREM4 for verification purposes. The measured two-dimensional TEM data obtained by chemical etching-method was consistent with the results of the developed analytical model, and it seemed to be more accurate than the results attained by a commercial TSUPREM4. The developed codes can be applied on a wider energy range $(1KeV{\sim}30MeV)$ than a commercial TSUPREM4 of which the maximum energy range cannot exceed 1MeV for the limited doping elements. Moreover, it is not only limited to diffusion process but also can be applied to implantation due to the sloped and nano scale structure of the mask.