• Journal of Powder Materials
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• v.15 no.5
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• pp.352-358
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• 2008

The present study focused on the synthesis of a bismuth-antimony-tellurium-based thermoelectric nanopowders using plasma arc discharge process. The chemical composition, phase structure, particle size of the synthesized powders under various synthesis conditions were analyzed using XRF, XRD and SEM. The powders as synthesized were sintered by the plasma activated sintering. The thermoelectric properties of sintered body were analyzed by measuring Seebeck coefficient, specific electric resistivity and thermal conductivity. The chemical composition of the synthesized Bi-Sb-Te-based powders approached that of the raw material with an increasing DC current of the are plasma. The synthesized Bi-Sb-Te-based powder consist of a mixed phase structure of the $Bi_{0.5}Sb_{1.5}Te_{3}$, $Bi_{2}Te_{3}$ and $Sb_{2}Te_{3}$ phases. This powder has homogeneous mixing state of two different particles in an average particle size; about 100nm and about 500nm. The figure of merit of the sintered body of the synthesized 18.75 wt.%Bi-24.68 wt.%Sb-56.57 wt.%Te nanopowder showed higher value than one of the sintered body of the mechanically milled 12.64 wt.%Bi-29.47 wt.%Sb-57.89 wt.%Te powder.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.276-279
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• 2009

ITO and ITO:Ce films were deposited by DC magnetron sputtering using an ITO ($SnO_2$: 10 wt%) and $CeO_2$ doped ITO ($CeO_2$: 0.5, 3.0, 4.0 and 6.0 wt%) ceramic targets, respectively, on unheated polyethylene terephthalate (PET) substrates. The lowest resistivity $6.7{\times}10^{-4}{\Omega}cm$ was obtained from ITO:Ce film deposited using $CeO_2$ (3.0 wt%) doped ITO target. On hte other hand, ITO:Ce (0.5wt%) film has the excellent mechanical durability which was evaluated by bending test. This result was attributed to the higher binding energy of $CeO_2$ compared to $SnO_2$ and $In_2O_3$. Therefore, $CeO_2$ atoms have a small displacement caused by the bombardment of high energy particles, and it attribute to the increase in adhesion caused by decrease in internal stress. The average transmittance of the films was more than 80% in the visible region.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1121-1124
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• 2004

Carbon Nitride exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) films. These diamond-like transport properties in Carbon Nitride come in a material consisting of $sp^2$-bonded carbon versus the $sp^3$-carbon of DLC. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. Liquid crystal (LC) alignment capabilities with ion beam exposure on carbon nitride thin films and Electro-Optical (EO) performances of the ion-beam aligned twisted nematic liquid crystal display (TN-LCD) with oblique ion beam exposure on the Carbon Nitride thin film surface were studied. An excellent uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the Carbon Nitride thin films was observed. In addition, the good EO properties of the ion-beam-aligned TN-LCD were achieved. Finally, we achieved the residual DC property of the ion-beam- aligned TN-LCD on the Carbon Nitride thin film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.62-65
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• 1995

CdTe crystals were grown by the vertical Bridgman method. P-type DcTe crystals were grown with Cd:Te= 1:1.001 wt. % ratio, while n-type CdTe crystals were 1:1 Also, CdTe:In crystals were investigated, Lattic constants were 6.489${\AA}$ for p-type 6.480${\AA}$for n=type and 6.483${\AA}$ for CdTe:In EPD was 10$\^$-3/-10$\^$4/cm$\^$-2/ for n-, p-type CdTd, 10$\^$4/-10$\^$5/cm$\^$-2 for Cd:Te:In using by E-Ag solution for (111) plane The carrier concentration, the resistivity and the Hall carrier mobility measured by the van der Pauw method were p=5.78${\times}$10$\^$15/cm$\^$-3/, $\rho$=20.2$\Omega$cm, ${\mu}$$\sub$p/=75.6cm$\^$-2/ V$\^$-1/ sec$\^$-1/ for p-typem n=2.98${\times}$10$\^$16/cm$\^$-3/, $\rho$=0.214$\Omega$cm, ${\mu}$$\sub$p/=978.9cm$\^$-2/ V$\^$-1/ sec$\^$-1/ for n-type and n=7.45${\times}$10$\^$16/cm$\^$-3/, $\rho$=1.54 ${\times}$10$\^$3/$\Omega$cm, ${\mu}$$\sub$p/=658.4 cm$\^$-2/ V$\^$-1/ sec$\^$-1/ for CdTe:In crystals, Transmittance of p-type CdTe was 61% that of n-type was 65%, Cd:Te:In showed 60% IR transmittance.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.105-109
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• 2007

In this paper, we fabricated TCO (transparent conductive oxide) electrode on flexible substrate in order to study effects of electrical and optical properties according to Al-doped ZnO(AZO) film thickness. The thickness of film was from 100 nm to 500 nm and was controlled by changing deposition time. We used High Resolution X-ray Diffractometer (HR-XRD) to analyze crystal structure and UV-visible spectrophotometer to measure property of optical transmittance, respectively. The surface images are obtained by using ESEM (Environment Scanning Electron Microscopy). In this experiment, all the AZO films deposited on flexible substrate show high transmittance over 90% and especially in the films with 400 nm and 500 nm thickness, the resistivity ($4.5{\times}10^{-3}\;{\Omega}-cm$) and optical bandgap energy (3.61 eV) are superior to the other films.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.6
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• pp.310-314
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• 2015

We have considered the influence of electron irradiation on the optical and electrical properties of $In_2O_3/Ti$ bi-layered films prepared with RF and DC magnetron sputtering. The $In_2O_3/Ti$ thin films irradiated at 600 eV shows the lowest resistivity of $6.9{\times}10^{-4}{\Omega}cm$. The optical transmittance in a visible wave length region also influenced with the electron irradiation energy. The film that electron irradiated at 600 eV shows 82.9% of optical transmittance in this study. By comparison of figure of merit, it is concluded that the opto-electrical performance of $In_2O_3/Ti$ bi-layered film is improved with electron irradiation.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1114-1123
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• 2015

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil-paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ. Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.172-188
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• 2000

This paper presents the state of art and the role of geophysical exploration techniques with evaluating the trend of domestic and worldwide seawater intrusion research, and illustrates advanced techniques obtained through the project of 'Development of the techniques for estimation, prediction, and prevention of seawater intrusion' funded by the Ministry of Science and Technology of Korea. The advanced geophysical interpretation was achieved by adding the digital geophysical logging data. DC resistivity and TEM monitorings were applied to determine whether or not the seawater intrusion was in progress. Induced Polarization technique using electric current monitoring channel was introduced to discriminate seawater contaminated zone from highly conductive layer caused by clay minerals. A conceptual model was suggested with spatial visualization of the study area to predict the diffusion of seawater contamination. Finally, the future work of the development of geophysical techniques was suggested with the base of the present level of them.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.127-127
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• 2011

We investigate the transparent TFTs using a transparent ZnSnO3 (ZTO)/Ag/ZTO multilayer electrode as S/D electrodes with low resistivity of $3.24{\times}10^{-5}$ ohm-cm, and high transparency of 86.29% in ZTO based TFTs. The Transparent TFTs (TTFTs) are prepared on glass substrate coated 100 nm of ITO thin film. On atomic layer deposited $Al_2\;O_3$, 50 nm ZTO layer is deposited by RF magnetron sputtering through a shadow mask for channel layer using ZTO target with 1 : 1 molar ratio of ZnO : $SnO_2$. The power of 100W, the working pressure of 2mTorr, and the gas flow of Ar 20 sccm during the ZTO deposition. After channel layer deposition, a ZTO (35 nm)/Ag (12 nm)/ZTO(35 nm) multilayer is deposited by DC/RF magnetron sputtering to form transparent S/D electrodes which are patterned through the shadow mask. Devices are annealed in air at 300$^{\circ}C$ for 30 min following ZTO deposition. Using UV/Visible spectrometer, the optical transmittances of the TTFT using ZTO/Ag/ ZTO multilayer electrodes are compared with TFT using Mo electrode. The structural properties of ZTO based TTFT with ZTO/Ag/ZTO multilayer electrodes are analyzed by high resolution transmission electron microscopy (HREM) and X-ray photoelectron spectroscopy (XPS). The transfer and output characterization of ZTO TTFTs are examined by a customized probe station with HP4145B system in are.

• Journal of the Korean institute of surface engineering
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• v.47 no.3
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• pp.109-115
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• 2014

High power impulse magnetron sputtering (HIPIMS), also known as the technology is called peak power density in a short period, you can get high, so high ionization sputtering rate can make. Higher ionization of sputtered species to a variety of coating materials conventional in the field of improving the characteristics and self-assisted ion thin film deposition process, which contributes to a superior being. HIPIMS at the same power, but the deposition speed is slow in comparison with DC disadvantages. Since recently as a replacement for HIPIMS modulated pulse power (MPP) has been developed. This ionization rate of the sputtered species can increase the deposition rate is lowered and at the same time to overcome the problems to be reported. The differences between the MPP and the HIPIMS is a simple single pulse with a HIPIMS whereas, MPP is 3 ms in pulse length is adjustable, with the full set of multi-pulses within the pulse period and the pulse is applied can be micro advantages. In this experiment, $In_2O_3$ : $SnO_2$ composition ratio of 9 : 1 wt% target was used, Ar : $O_2$ flow rate ratio is 4.8 to 13.0% of the rate of deposition was carried out at room temperature. Ar 40 sccm and the flow rate of $O_2$ and then fixed 2 ~ 6 sccm was compared against that. The thickness of the thin film deposition is fixed at 60 nm, when the partial pressure of oxygen at 9.1%, the specific resistance value of $4.565{\times}10^{-4}{\Omega}cm$, transmittance 86.6%, mobility $32.29cm^2/Vs$ to obtain the value.