• Journal of Integrative Natural Science
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• v.5 no.4
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• pp.211-215
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• 2012

Single-crystalline silicon nanowire arrays (SiNWAs) using electroless metal-assisted etchings of p-type silicon were successfully fabricated. Ag nanoparticle deposition on silicon wafers in HF solution acted as a localized micro-electrochemical redox reaction process in which both anodic and cathodic process took place simultaneously at the silicon surface to give SiNWAs. The growth effect of SiNWs was investigated by changing of etching times. The morphologies of SiNWAs were obtained by SEM observation. Well-aligned nanowire arrays perpendicular to the surface of the silicon substrate were produced. Optical characteristics of SiNWs were measured by FT-IR spectroscopy and indicated that the surface of SiNWs are terminated with hydrogen. The thicknesses and lengths of SiNWs are typically 150-250 nm and 2 to 5 microns, respectively.

• Journal of Korean Society for Quality Management
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• v.42 no.2
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• pp.179-187
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• 2014

Purpose: Since several problems were found when present non-conducting metal coating process was applied to mass production, we study and develop to improve those problems. Methods: In this paper, a couple of analysis methods such as surface hardness, XPS spectrum analysis, morphology, and reflection ratio were used. Results: This paper suggest a new possibility of Non-conducting thin metal coating method that has quality of mass production phase without UV coating process. Conclusion: By the result of analysis, we can set optimized process conditions of the electro deposition coating using electron beam.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.987-989
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• 2006

1.52" $130(RGB){\times}130$ full color PM OLED device with $70\;{\mu}m{\times}210\;{\mu}m$ of sub-pixel pitch was fabricated using shadow mask method for metal cathode deposition. Instead of conventional patterning process to form cathode separator via photolithography, regularly patterned shadow mask was applied to deposit metal cathode in this OLED display. Metal cathode was patterned via 2-step evaporation using shadow mask with shape of rectangular stripe and its alignment margin is $2.5\;{\mu}m$. Technical advantages of this method include reduction of process time according to skipping over photolithographic process for cathode separator and minimizing pixel shrinkage caused by PR cathode separator as well as improving lifetime of OLED device.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.155-160
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• 2012

This paper reported a simple deposition-precipitation method, introducing the metal (Ni, Ag and Sn) and $Na_2S{\cdot}5H_2O$ to preparedispersion metal sulfide nanoparticles on the surface of the Multi-walled carbon nanotube for synthesis of CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composite photocatalysts. The characterization of the prepared CNT-$M_xS_y$ ($NiS_2$, $Ag_2S$, SnS) composites was performed by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis and BET analysis. Furthermore, the MB degradation rate constant for CNT-SnS composite was $5.68{\times}10^{-3}$ under visible light irradiation, which was much higher than the corresponding values for other samples. The detailed formation and photocatalytic mechanism are also provided here.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1147-1148
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• 2015

This study demonstrates the coating effect of carbon nanotubes on metal meshes, which have been made with various line-spaces and line-width, for touch screen panels. The CNTs have been deposited on metal meshes via electrophoretic deposition (EPD). The sheet resistances, visible transmittances, visible reflectances have been measured before and after electrophoretic deposition. The experimental results confirm that CNT coating metal meshes with various line-spaces and line width can satisfy the requirements that are required for transparent electrodes of touch screen panels.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.240-241
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• 2006

Metal/diamond binary composite coatings on Al substrate without grit blasting were deposited by cold spray process with insitu powder preheating. Microstructural characterization of the as-sprayed coatings with different diamond size, strength and with/without Ti coating on diamond was carried out by OM and SEM. The assessment of basic properties such as tensile bond strength and hardness of the coatings, and the deposition efficiency was also carried out. Particular attention on the composite coatings was on the diamond fracture phenomenon during the cold spray deposition and the interface bonding between the diamond and the Fe-based metal matrix.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.73-73
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• 1999

A large area negative metal ion beam source is developed. Kinetic ion beam of the incident metal ions yields a whole nucleation and growth phenomena compared to the conventional thin film deposition processes. At the initial deposition step one can engineer the surface and interface by tuning the energy of the incident metal ion beams. Smoothness and shallow implantation can be tailored according to the desired application process. Surface chemistry and nucleation process is also controlled by the energy of the direct metal ion beams. Each individual metal ion beams with specific energy undergoes super-thermodynamic reactions and nucleation. degree of formation of tetrahedral Sp3 carbon films and beta-carbon nitride directly depends on the energy of the ion beams. Grain size and formation of polycrystalline Si, at temperatures lower than 500deg. C is obtained and controlled by the energy of the incident Si-ion beams. The large area metal ion source combines the advantages of those magnetron sputter and SKIONs prior cesium activated metal ion source. The ion beam source produces uniform amorphous diamond films over 6 diameter. The films are now investigated for applications such as field emission display emitter materials, protective coatings for computer hard disk and head, and other protective optical coatings. The performance of the ion beam source and recent applications will be presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.13-15
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• 2005

The growth of $Bi_2Te_3$ thin films on (001) GaAs substrates by metal organic chemical vapour deposition (MOCVD) is discussed in this paper. The results of surface morphology, electrical and thermoelectrical properties as a function of growth parameters are given. The surface morphologies of $Bi_2Te_3$ films were strong1y dependent on the deposition temperatures. Surface morphologies varied from step-flow growth mode to island coalescence structures depending on deposition temperature. In-plane carrier concentration and electrical Hall mobility were highly dependent on precursor's ratio of Te/Bi and deposition temperature. The high Seebeck coefficient (of $-160{\mu}VK^{-1}$) and good surface morphology of our result is promising for $Bi_2Te_3$ based thermoelectric thin film and two dimensional supperlattice device applications.

• Progress in Superconductivity
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• v.12 no.1
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• pp.68-73
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• 2010

Y123 films have been deposited on $LaAlO_3$ (100) single-crystal and IBAD substrates by spray pyrolysis method using nitrate precursors. Ultrasonic atomization was adopted to decrease the droplet size, spraying angle and its moving velocity toward substrate for introducing the preheating tube furnace in appropriate location. A small preheating tube furnace was installed between spraying nozzle and substrate for fast drying and enhanced decomposition of precursors. C-axis oriented films were obtained on both LAO and IBAD substrates at deposition temperature of around $710{\sim}750^{\circ}C$ and working pressures of 10~15 torr. Thick c-axis epitaxial film with the thickness of $0.3{\sim}0.6\;{\mu}m$ was obtained on LAO single-crystal by 10 min deposition. But the XRD results of the film deposited on IBAD template at same deposition condition showed that the buffer layers of the IBAD metal substrate was affected by long residence of metal substrate at high temperature for YBCO deposition.

• Laser Solutions
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• v.18 no.3
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• pp.1-5
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• 2015

A 3D printer based on laser powder deposition (LPD), also known as DED (direct energy deposition), has been developed for fabricating metal parts. The printer uses a ytterbium fiber laser (1070nm, 1kW) and is equipped with an Ar purge chamber, a three-dimensional translation stage and a powder feeding system composed of a powder chamber and delivery nozzles. To demonstrate the performance of the printer, a tapered cylinder of 320mm in height has been fabricated successfully using Ti-6Al-4V powders. The process parameters including the laser output power, the scan speed, and the powder feeding rate have been optimized. A 3D printed test specimen shows mechanical properties (yield strength, ultimate tensile strength, and elongation) exceeding the criteria to employed in a variety of Ti alloy applications.