• Korean Journal of Materials Research
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• v.21 no.5
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• pp.255-262
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• 2011

This paper has relatively high technical standard and experimental skill. The fabrication of TCO film with high transparency, low resistance and low chromaticity require exact control of several competing factors. This paper has resolved these problems reasonably well, thus recommended for publication. Indium tin oxide(ITO) thin films were by D.C. magnetron roll-to-roll sputter system utilizing ITO and $SiO_2$ targets of ITO and $SiO_2$. In this experiment, the effect of D.C. power, winding speed, and oxygen flow rate on electrical and optical properties of ITO thin films were investigated from the view point of sheet resistance, transmittance, and chromaticity($b^*$). The deposition of $SiO_2$ was performed with RF power of 400W, Ar gas of 50 sccm and the deposition of ITO, DC power of 600W, Ar gas of 50 sccm, $O^2$ gas of 0.2 sccm, and winding speed of 0.56m/min. High quality ITO thin films without $SiO_2$ layer had chromaticity of 2.87, sheet resistivity of 400 ohm/square, and transmittance of 88% and $SiO_2$-doped ITO Thin film with chromaticity of 2.01, sheet resistivity of 709 ohm/square, and transmittance of more than 90% were obtained. As a result, $SiO_2$ was coated on PET before deposition of ITO, their chromaticity($b^*$) and transmittance were better than previous results of ITO films. These results show that coating of $SiO_2$ induced arising chromaticity($b^*$) and transmittance. If the thickness of $SiO_2$ is controlled, sheet resistance value of ITO film will be expected to be better for touch screen. A four point probe and spectrophotometer are used to investigate the properties of ITO thin films.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.128-133
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• 2007

In this study, we observed the shapes of CNTs formed with the thinckness of catalyst. Catalyst layer was grown by magnetron sputtering method and the thickness of Ni catalyst is the range from 20 to 80 nm. Also, the synthesis of CNT with Ni catalyst thickness was grown by hot-filament PECVD method. And, we investigated the composition of CNTs by using EDS measurement, also observed the shapes of CNTs by using HRTEM and FESEM measurements. In the result, through the TEM analysis, we observed the empty inside of CNTs and the multiwall CNTs, also confirmed the tip of CNT containing Ni. The composition of CNTs are consisted of an element of C, Ti, and Ni. As you shown the growth shapes of CNTs, the pretreatment of the catalyst before te growth of CNTs changed the particle size of the catalysts and grown the CNTs of the different shapes. Consequently, the best vertically alined and well-arranged CNTs exhibited from the substrate deposited at the catalyst thickness of 40 nm.

• Journal of the Korean Ceramic Society
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• v.42 no.1
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• pp.43-49
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• 2005

YSZ layer containing nano-sized particles has been deposited on the commercial A1203 substrate by Electron Beam Physical Vapor Deposition (EB-PVD). The role of coating rnjcrostructures of YSZ to indentation damage is studied. The different coating microsouctures are prepared by varying the substrate temperatures from $600^{circ}C$ to $800^{circ}C$ during the deposition. Microhardness test and Hertzian indentation are conducted on the $YSZ/Al_{2}O_{3}$ layered systems. The damage and flilure behaviors have been investigated according to the effect of microstructures and indentation loads. With increasing the substrate temperature during EB-PVD, the overall grain sizes are coarser and more faceted, which microsoucture ultimately influences on the indentation behavior, thus, YSZ/Al_{2}O_{3}$ layered system prepared at the substrate temperature of $800^{circ}C$ shows relatively higher damage tolerance.

• Journal of the Korean Vacuum Society
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• v.21 no.3
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• pp.178-184
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• 2012

Carbon coils could be synthesized on nickel catalyst layer-deposited silicon oxide substrate using $C_2H_2$ and $H_2$ as source gases and $SF_6$ as an additive gas under thermal chemical vapor deposition system. The characteristics (formation density and morphology) of as-grown carbon coils were investigated as functions of additive gas flow rate and the cycling on/off modulation of $C_2H_2/SF_6$ flows. Even in the lowest $SF_6$ flow rate (5 sccm) in this work, the cycling on/off modulation injection of $SF_6$ flow for 2 minutes could give rise to the formation of nanosized carbon coils, whereas the continuous injection of $SF_6$ flow for 5 minutes could not give rise to the carbon coils formation. With increasing $SF_6$ flow rates from 5 to 30 sccm, the cycling on/off modulation injection of $SF_6$ flow confines the geometry for the carbon coils to the nanosized ones. Fluorine's role of $SF_6$ during the reaction was regarded as the main cause for the confinement of carbon coils geometries to the nano-sized ones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.105-112
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• 2018

This paper proposes a method for fabricating heatable glass using the conduction characteristics of metal thin films deposited on the surface of Low-e(Low emissivity) glass. The heating value of Low-e glass depends on the Joule heat caused by Low-e glass sheet resistance. Hence, its prediction and design are possible by measuring the sheet resistance of the material. In this study, silver electrodes were placed at 50 mm intervals on a soft Low-e glass sample with a low emissivity layer of 11 nm. This study measured the sheet resistance using a 4-point probe, predicted the power consumption and heating value of the Low-e glass, and confirmed the heating performance through fabrication and experience. There are two conventional methods for manufacturing heatable glass. One is a method of inserting nichrome heating wire into normal glass, and the other is a method of depositing a conductive transparent thin film on normal glass. The method of inserting nichrome heating wire is excellent in terms of the heating performance, but it damages the transparency of the glass. The method for depositing a conductive transparent thin film is good in terms of transparency, but its practicality is low because of its complicated process. This paper proposes a method for manufacturing heatable glass with the desired heating performance using Low-e glass, which is used mainly to improve the insulation performance of a building. That is by emitting a laser beam to the conductive metal film coated on the entire surface of the Low-e glass. The proposed method is superior in terms of transparency to the conventional method of inserting nichrome heating wire, and the manufacturing process is simpler than the method of depositing a conductive transparent thin film. In addition, the heat characteristics were compared according to the patterning of the surface thin film of the Low-e glass by an emitting laser and the laser output conditions suitable for Low-e glass.

• Journal of the Korean Vacuum Society
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• v.15 no.3
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• pp.287-293
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• 2006

Diamond-like carbon (DLC) film was deposited using benzene $(C_6H_6)$ by r. f-plasma assisted chemical vapor deposition. The tribological properties of the DLC film were tested by rotating ball-on-disc type tribometer isolated by a chamber. The tribological test was performed in air environment of relative humidity ranging from 0 to 90% in order to observe the tribological behavior of the DLC film with the change of humidity. We used steel ball and DLC coated steel ball to investigate the effect of the counterface material. Using steel ball, the friction coefficient of DLC film increased from 0.025 to 0.2 as the humidity increased from 0% to 90%. In case of DLC coated steel ball which didn't form the Fe-rich debris, the friction coefficient showed much lower dependence of humidity as 0.08 in relative humidity 90%. We confirmed that the high humidity dependence of the friction coefficient using steel ball resulted from the increase of debris size with humidity and the formation of Fe-rich debris by the wear of steel ball. And the friction coefficient was immediately dropped when the relative humidity changed from 90% to 0% during test using steel ball. From this result, we confirmed that the effect of the Fe-rich debris on the friction coefficient was that Fe element in debris formed the highly sensitive graphitic transfer layer to humidity.

• Journal of the Korean Vacuum Society
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• v.21 no.1
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• pp.12-16
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• 2012

Although silver is used for T-OLED (Top emitting organic Light-Emitting Diode) as reflective anode, it is not an ideal material due to its low work function. Thus, we study the effect of annealing and atmospheric pressure plasma treatment on Ag film that increases its work function by forming the thin silver oxide layer on its surface. In this study, we deposited silver on glass substrate using RF sputtering. Then we treated the Ag samples annealing at $300^{\circ}C$ for 30 minutes in atmosphere or treating the atmospheric plasma treatment for 30, 60, 90, 120s, respectively. We measured the change of the mechanical properties and the potential value of surface with each one at a different treatment type and time. We used nano-indenter system and KPFM (Kelvin Probe Force Microscopy). KPFM method can be measured the change of surface potential. The nanoindenter results showed that the plasma treatment samples for 30s, 120s had very low elastic modulus, hardness and Weibull modulus. However, annealed sample and plasma treated samples for 60s and 90s had better mechanical properties. Therefore, plasma treatment increases the uniformity thin film and the surface potential that is very effective for the performace of T-OLED.

• Journal of the Korean Vacuum Society
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• v.21 no.1
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• pp.48-54
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• 2012

Carbon coils could be synthesized on nickel catalyst layer-deposited silicon oxide substrate using $C_2H_2$ and $H_2$ as source gases and SF6 as an additive gas under thermal chemical vapor deposition system. The geometries of as-grown carbon materials were investigated with increasing the reaction temperature as the increment of $25^{\circ}C$ from $650^{\circ}C$ up to $800^{\circ}C$. At $650^{\circ}C$, the embryos for carbon coils were formed. With increasing the reaction temperature to $700^{\circ}C$, the coil-type geometries were developed. Further increasing the reaction temperature to $775^{\circ}C$, the development of wave-like nano-sized coils, instead of nano-sized coils, and occasional appearance of micro-sized carbon coils could be observed. Fluorine in $SF_6$ additive may shrink the micro-sized coil diameter via the reduction of Ni catalyst size by fluorine's etching role. Finally, the preparation of the micro-sized carbon coils having the smaller coil diameters, compared with the previously reported ones, could be possible using $SF_6$ additive.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.115-121
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• 2013

We fabricated thin film transistors (TFTs) using TiInZnO(TiIZO) thin films as active channel layer. The thin films of TiIZO were deposited at room temperature by RF-magnetron co-sputtering system from InZnO(IZO) and Ti targets. We examined the effects of titanium addition by X-ray diffraction, X-ray photoelectron spectroscopy and the electrical characteristics of the TFTs. The TiIZO TFTs were investigated according to the radio-frequency power applied to the Ti target. We found that the transistor on-off currents were greatly influenced by the composition of titanium addition, which suppressed the formation of oxygen vacancies, because of the stronger oxidation tendency of Ti relative to that of Zn or In. A optimized TiIZO TFT with rf power 40W of Ti target showed good performance with an on/off current ratio greater than $10^5$, a field-effect mobility of 2.09 [$cm^2/V{\cdot}s$], a threshold voltage of 2.2 [V] and a subthreshold swing of 0.492 [V/dec.].

• Journal of Chest Surgery
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• v.37 no.4
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• pp.307-312
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• 2004

With the development of cardiac surgical technique, we need more prosthetic materials for repairing the intra- and extracardiac defects. Although bovine pericardial bioprosthesis treated with glutaraldehyde (GA) solution is one of the most popular materials, it has a drawback of later calcific degeneration. The purpose of this study is to investigate the effectiveness of several materials and methods in reducing the calcific degeneration of bovine pericardium. Material and Method: Forty square-shaped pieces of bovine pericardia were fixed in 0.625% GA solution with 4 g/L MgCl$_2$ㆍ6$H_2O$ as a control group (group 1). Other 40 pieces pre-treated with 1 % SDS(group 2) and 40 pieces post-treated with 8% glutamate (group 3) and 2% chitosan (group 4) were also fixed in the same GA solution. Other 40 pieces pre-treated with 1% SDS and post-treated with 8% glutamate and 40 pieces post-treated with 2% chitosan were also fixed in the same GA solution (group 5, 6). The pericardial pieces were implanted into the belly of 40 Fisher 344 rats subdermally and were extracted 1 month, 2 months, 3 months, and 6 months after the implantation. With an atomic absorption spectrophotometry, we measured the calcium amount deposited and examined the tissue with microscope. Result: The calcium deposition in 1 month was less in group 2, 5, 6 than that in group 1 (p＜0.05). It was most prominent in group 5 (p＜0.01). This finding continued in 2 month. In 3 month, the calcium deposition was less in group 3 and 4 as well as group 2, 5, and 6 than in group 1. In 6 month, the calcium deposition in group 2, 3, 4, 5, and 6 was less than that in group 1 and the difference was more than that of 1, 2, and 6 month. The microscopic calcium deposition was also less in group 2 and 5. Calcium deposition developed in the whole layer of pericardium, beginning with the surrounding the collagen fiber and progressing inwardly. Conclusion: Pre-treatment with SDS, post-treatment with glutamate or chitosan, and SDS pre-treatment and post-treatment with glutamate or chitosan were effective in reducing the calcium deposition in bovine pericardium. Moreover, the combined method of SDS pre-treatment and glutamate post-treatment was more effective than other methods.