• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.736-740
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• 2010

Nickel wires of 0.8 mm in diameter and 80 mm in length were electrically exploded in liquid media such as water, ethyl alcohol. The distribution of particle sizes was broad from a few micrometers to tens of nanometer. It was identified that the particles could be classified according to its sizes by using centrifugal separator. The powder prepared in distilled water showed mainly pure metallic Ni phase although a little oxide phase was observed. The powders prepared in ethyl alcohol showed complicated unknown phases, which is attributed to the compound of carbon in the organic liquid. This unknown phase was turned to pure metallic Ni phase after heat treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.5
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• pp.349-352
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• 2012

ZnO thin films were deposited on a-, c- and m- plane oriented 4H-SiC substrates by pulsed laser deposition. ZnO nanowires were formed on substrates by tube furnace. Shape and density of the ZnO nanowires were investigated by field emission scanning electron microscope. Average surface roughness and root mean square surface roughness were measure by atomic force microscope. Optical properties were investigated by Photoluminescence measurement. Density of ZnO nanowires grown on a-, c- and m-plane oriented 4H-SiC substrates were 17.89 ${\mu}m^{-2}$, 9.98 ${\mu}m^{-2}$ and 2.61 ${\mu}m^{-2}$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.317-321
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• 2014

Hydrothermal synthesis technique could be carried out for growth of ZnO nanowires at relatively low process temperature, and it could be freely utilized with various substrates for fabrication process of functional electronic devices. However, it has also a demerit of relatively slow growth characteristics of the resulting ZnO nanowires. In this paper, an external DC bias of positive and negative 0.5 [V] was applied in the hydrothermal synthesis process for 2~8 [h] to prepare ZnO nanowires on a seed layer of AZO with high electrical conductivity. Growth characteristics of the synthesized ZnO nanowires were analyzed by FE-SEM. Material property of the grown ZnO nanowires was examined by PL analysis. The ZnO nanowires grown with positive bias revealed distinctively enhanced growth characteristics, and they showed a typical material property of ZnO.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.185-191
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• 2017

Cadmium compounds with one dimension (1D) nanostructures have attracted attention for their excellent electrical and optical properties. In this study, vertically aligned CdTe-Si nanostructures with high density were synthesized by several simple chemical reactions. First, l D Te nanostructures were synthesized by silver assisted chemical Si wafer etching followed by a galvanic displacement reaction of the etched Si nanowires. Nanowire length was controlled from 1 to $25{\mu}m$ by adjusting etching time. The Si nanowire galvanic displacement reaction in $HTeO_2{^+}$ electrolyte created hybrid 1D Te-branched Si nanostructures. The sequential topochemical reaction resulted in $Ag_2Te-Si$ nanostructures, and the cation exchange reaction with the hybrid 1D Te-branched Si nanostructures resulted in CdTe-Si nanostructures. Wet chemical processes including metal assisted etching, galvanic displacement, topochemical and cation exchange reactions are proposed as simple routes to fabricate large scale, vertically aligned CdTe-Si hybrid nanostructures with high density.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.325-329
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• 2013

Carbon nanotubes(CNT) have excellent electrical, chemical stability and mechanical properties. These can be used in a variety of fields. MWCNT are extremely sensitive for minute changes in the ambient gas, namely, their sensing properties varies greatly with the absorption of gas such as NOx and $H_2$. We investigate the electrical properties of CNTs and make a NOx gas sensor based on Multi-walled carbon nanotubes (MWCNT) materials. We obtained the NOx gas sensor of MWCNT based on P-type Si wafer that has the resistivity of $1.667{\times}10^{-1}[{\Omega}{\cdot}cm]$. We knew that the sensitivity of sensor decreased with increasing of NOx gas concentration. And the sensitivity of sensor shows the largest value at $20^{\circ}C$. The sensitivity of sensor decrease with increasing the temperature. Also absorption energy of NOx gas molecule on the MWCNT surface decreases with increasing concentration of NOx gas.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.441-445
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• 2013

ZnO nanowires on the a-, c- and m-plane oriented 4H-SiC substrates were grown by using a high temperature tube furnace. Ti/Au electrodes were deposited on ZnO nanowires and a-, c- and m-plane 4H-SiC substrates, respectively. The shape and density of the ZnO nanowires were investigated by field emission scanning electron microscope. It was found that the growth direction of nanowires depends strongly on growth parameters such as growth temperature and pressure. In this work, The sensitivity of nanowires formed a-, c- and m-plane oriented 4H-SiC gas sensor was measured at $300^{\circ}C$ with CO gas concentration of 80%. The nanowires grown on a-plane oriented 4H-SiC show improved sensing performance than those on c- and m-plane oriented 4H-SiC due to the increased density of nanowire on a-plane 4H-SiC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.2
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• pp.80-84
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• 2018

In this study, we investigated plasmon effects to maximize the sterilization of dielectric discharge. We predicted the effect using the finite difference time domain (FDTD) method as a function of electrode shape, size, and period. The structure of the electrode was designed with a thickness of 100 nm of silver nanoparticles on a glass substrate, and was varied according to the shape, size, and period of the electrode hole. Based on the results, it was confirmed that the effect of plasmons was independent of the shape of the electrode hole. It was thus confirmed that the plasmon effect depended only on the size and period of the holes. Further, the plasmon effect was affected by the size rather than period of the holes. Because the absorption of light by the metal varied according to the size of the hole, the plasmon effect generated by the absorption of light also varied. The best results were obtained when the radius and period of the electrode holes were $0.1{\mu}m$ and $0.4{\mu}m$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.917-923
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• 2005

In this paper, effect of catalytic configuration on the sensing properties of $SnO_2$ nanoparticle gas sensitive thick film was investigated. Two types of catalytic configuration, mono and binary, were made on the $SnO_2$ nanoparticle. In case of mono catalytic system, $3 wt\%$ Pd or Pt catalyst was doped onto the $SnO_2$ nanoparticle, respectively. In case of binary catalytic system, Pd and Pt was doped simultaneously with concentration ratio of 1:2 to 2:1 onto the $SnO_2$ nanoparticle. After doping, gas sensitive thick film was printed on alumina substrate and heat-treated at 450 to $600^{\circ}C$. Gas sensing properties was evaluated using 500 to 10,000 ppm $CH_4$ gas. As a result, gas sensitive thick film with binary catalytic system showed unstable phenomena that the gas sensitivity was changed according to aging time. In contrary, the mono catalytic system showed relatively stable phenomena despite of aging time. Especially, gas sensitive thick film doped with $3 wt\%$ Pt catalyst and heat-treated at $500^{\circ}C$ showed good sensing properties such as 0.57 of $R_{3500}/R_{1000}$ and very small variation within $3.5\%$ after aging for 5 hours, and response time was very short less than 20 seconds.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.189-194
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• 2006

Ordered nanostructure materials have received attention due to their unique physical properties and potential applications in electronics, mechanics and optical devices. To actualize most of the proposed applications, it is quite important to obtain highly ordered nanostructure arrays. The well-aligned nanostructure can be achieved by synthesizing nanostructure material in the highly ordered template. To get well-aligned pore array and reduce process time, rapid thermal anneal by an IR lamp was employed in vacuum state at $500^{\circ}C$ for 2 hour. The pore array is comparable to a template annealed in vacuum furnace at $500^{\circ}C$ for 30 hours. The well-fabricated AAO template has the mean pore diameter of 70 nm, the barrier layer thickness of 25 nm, the pore depth of $9{\mu}m$, and the pore density of higher than $1.2{\times}10^{10}cm^{-2}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.116-125
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• 2006

We have presented a nanoelectromechanical (NEM) model based on atomistic simulations. Our models were applied to a NEM device as called a nanotube random access memory (NRAM) operated by an atomistic capacitive model including a tunneling current model. We have performed both static and dynamic analyses of a NRAM device. The turn-on voltage obtained from molecular dynamics simulations was less than the half of the turn-on voltage obtained from the static simulation. Since the suspended carbon nanotube (CNT) oscillated with the amplitude for the oscillation center under an externally applied force, the quantity of the CNT-gold interaction in the static analysis was different from that in the dynamic analysis. When the gate bias was applied, the oscillation centers obtained from the static analysis were different from those obtained from the dynamics analysis. Therefore, for the range of the potential difference that the CNT-gold interaction effects in the static analysis were negligible, the vibrations of the CNT in the dynamics analysis significantly affected the CNT-gold interaction energy and the turn-on voltage. The turn-on voltage and the tunneling resistance obtained from our tunneling current model were in good agreement with previous experimental and theoretical works.