• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.90-90
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• 2011

Transparent conducting oxide (TCO) films have been intensively utilized in the electric applications, such as, displays, lightings and solar cells due to the good electric conductivity with an excellent transmittance of the visible light. We, herein present an excellent Al-doped ZnO film (AZO), which has been fabricated by co-sputtering method. An as-deposited AZO film had an optical transmittance of 84.78% at 550 nm and a resistivity of $7.8{\times}10^{-3}{\Omega}cm$. A rapid annealing process significantly improved the optical transmittance and electrical resistivity of the AZO film to 99.67% and $1{\times}10^{-3}{\Omega}cm$, respectively. The fabricated AZO film was fabricated for a metal-semiconductor-metal (MSM) structure. The AZO film-embedding MSM device was highly responsive to a UV light.

• Proceedings of the Korean Geotechical Society Conference
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• 1992.12a
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• pp.33-66
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• 1992

Recently, waste landfills built on seashores have been increased because of the easy availability of broad area near the urban communities. To evaluate the performance of the marine clay landfill liner numerical contaminant transport analyses are performed by selecting the typical section of a waste landfill built on seashores and using hydraulic conductivity data obtained from the site. Also, the laboratory electrical resistivity test and the in-situ corrosion test are performed in order to analyze the influence of the soil and leachates composing the landfills on the construct ion materials. From the results of contaminant transport analyses, it is shown that the leachates can be migrated faster through narrow pervious channels than the wide homogeneous pervious tedium and the importance of good quality barriers to prevent the contaminant migration is recognized. In the laboratory electrical resistivity test all the earth materials except the cover soils saturated with distilled water have small resistivities, which shows a high potential of corrosivity of soils composing landfills. However, the degree of corrosion of specimens buried in the landfills was not so severe except the zinc and carbon steel specimens. This apparently conflict results present the necessity of the investigation of other major factors and the long term in-situ corrosion test.

• Korean Journal of Materials Research
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• v.15 no.8
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• pp.514-517
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• 2005

Effects of nitrogen and oxygen annealing on the carrier concentration, carrier mobility, electrical resistivity and PL characteristics as well as the crystallinity of ZnO films deposited on sapphire substrates by atomic layer deposition (ALD). X-ray diffraction (XRD), Scanning electron microscope (SEM), photoluminescence (PL) analyses, and Hall measurement were performed to investigate the crystallinity, optical properties and electrical properties of the ZnO thin films, respectively. According to the XRD analysis results the crystallinity of the ZnO film annealed in an oxygen atmosphere is better than that of the ZnO film annealed in a nitrogen atmosphere. Annealing undoped ZnO films grown by ALD at a high temperature above $600^{\circ}C$ improves the crystallinity and enhances W emission but deteriorates the electrical conductivity of the flms. The resistivity of the ZnO film annealed particularly at $800^[\circ}C$ in a nitrogen atmosphere is much higher than that annealed at the same temperature in an oxygen atmosphere.

• Korean Journal of Materials Research
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• v.11 no.9
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• pp.802-809
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• 2001

Electroplating is an attractive alternative deposition method for copper with the need for a conformal and conductive seed layer In addition, the Cu seed layer should be highly pure so as not to compromise the effective resistivity of the filled copper interconnect structure. This seed layer requires low electrical resistivity, low levels of impurities, smooth interface, good adhesion to the barrier metal and low thickness concurrent with coherence for ensuring void-free fill. The electrical conductivity of the surface plays an important role in formation of initial Cu nuclei, Cu nucleation is much easier on the substrate with higher electrical conductivities. It is also known that the nucleation processes of Cu are very sensitive to surface condition. In this study, copper seed layers deposited by magnetron sputtering onto a tantalum nitride barrier layer were used for electroplating copper in the forward pulsed mode. Prior to electroplating a copper film, the Cu seed layer was cleaned by plasma H$_2$ and $N_2$. In the plasma treatment exposure tome was varied from 1 to 20 min and plasma power from 20 to 140W. Effects of plasma pretreatment to Cu seed/Tantalum nitride (TaN)/borophosphosilicate glass (BPSG) samples on electroplating of copper (Cu) films were investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1693-1706
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• 2008

It is of importance to determine the zero effective stress void ratio($e_{00}$), which is the void ratio at effective stress equal to zero, and the relationships of void ratio-effective stress and of void ratio-hydraulic conductivity for characterizing non-liner finite strain consolidation behavior for ultra-soft dredged materials. The zero effective stress void ratio means a transitional status from sedimentation to self-weight consolidation of very soft soil deposits, and acts as a starting point for self-weight consolidation in the non-linear finite strain numerical analysis such as PSDDF. In this paper, a new method for determining the zero effective stress void ratio has been introduced with the aid of measuring electrical resistivity of the specimen. A correlation between the zero effective stress void ratio and the initial slurry void ratio has been proposed, which can be used in PSDDF analysis as an input parameter. Combining all of the accessible experimental data, the consolidation characteristics of a dredged soil from the Incheon area has been studied in detail.

• Elastomers and Composites
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• v.56 no.2
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• pp.65-71
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• 2021

In recent times, the demand for electronic devices has increased because of advancements in the electronics industry. Consequently, research on shielding against electromagnetic interference (EMI) from electronic devices has also progressed significantly. In particular, research on imparting electrical conductivity to plastic has seen substantial progress. In this study, the effect of hybrid fillers comprising carbon fiber (CF) and carbon nanotubes (CNTs) on the electrical properties of polyamide 66 (PA66) composites was investigated. PA66 composites were prepared using a BUSS Co-Kneader single-screw extruder. EMI shielding effectiveness (SE) increased with the increasing addition of unsized CF (UCF), sized CF (SCF), and CNTs. For the PA66/SCF/CNT hybrid filler composites, EMI SE significantly increased with the increase in SCF content. Finally, the hybrid filler comprising SCF and CNTs may have a synergistic effect on the EMI SE and surface resistivity of PA66/SCF/CNT composites.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.288-294
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• 2011

Simultaneous Ni and C codeposition by electrolysis was investigated with the aim of obtaining better corrosion resistivity and surface conductivity of a metallic bipolar plate for application in fuel cells and redox flow batteries. The carbon content in the Ni-C composite plate fell in a range of 9.2~26.2 at.% as the amount of carbon in the Ni Watt bath and the roughness of the composite were increased. The Ni-C composite with more than 21.6 at.% C content did not show uniformly dispersed carbon. It also displayed micro-sized defects such as cracks and crevices, which result in pitting or crevice corrosion. The corrosion resistance of the Ni-C composite in sulfuric acid is similar with that of pure Ni. Electrochemical test results such as passivation were not satisfactory; however, the Ni-C composite still displayed less than $10^{-4}$ $A/cm^2$ passivation current density. Passivation by an anodizing technique could yield better corrosion resistance in the Ni-C composite, approaching that of pure Ni plating. Surface resistivity of pure Ni after passivation was increased by about 8% compared to pure Ni. On the other hand, the surface resistivity of the Ni-C composite with 13 at.% C content was increased by only 1%. It can be confirmed that the metal plate electrodeposited Ni-C composite can be applied as a bipolar plate for fuel cells and redox flow batteries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.270-271
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• 2008

Antimony (6 wt%) doped tin oxide (ATO) films to improve conductivity were deposited on 7059 coming glass by RF magnetron sputtering method for application to transparent electrodes. The ATO film was deposited at a working pressure of 5 mTorr and RF power of 175 W. We investigated the effects of the post-annealing temperature on structural, electrical and optical properties of the ATO films. The films were annealed at temperatures ranging from $300^{\circ}C$ to $600^{\circ}C$ in step of $100^{\circ}C$ using RTA equipment in vacuum ambient. X-ray diffraction (XRD) measurements showed the ATO films to be crystallized with a strong (101) preferred orientation as the annealing temperature increased. Electrical resistivity decreased significantly with annealing temperatures up to $600^{\circ}C$. ATO film annealed at temperature of $600^{\circ}C$ showed the lowest resistivity of $5.6\times10^{-3}\Omega$-cm. Optical transmittance increased significantly with annealing temperatures up to $600^{\circ}C$. The highest transmittance was 90.8 % in the visible range from 400 to 800 nm.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.105-110
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• 1997

1μm-CdS films for a window layer of CdS/CuInSe2 solar cell have been prepared by vacuum of 1x10-3 mTorr. Source and substrate temperature ranges were used 800-1100'C and 50-200℃ respectively. Structural, electircal and optical properties of CdS films have been investigated by X-ray diffractometer (XRD), scanning electron microscopy (SSEM), electrical resistivity, the Hall measurement and optical transmission spectra. Electrical resistivity and optical transmission of the CdS films decreased with the increase in CdS source temperature without substrate heating. All the films had hexagonal structure and strong texture with (002) orientation of grain normal to the substrate glass. CdS films evaporated at 1000℃ were the highest electrical conductivity of 0.9(S/cm). Electrical resistivity and optical transmission at the substrate temperature of 100℃ were 40(Ω,cm) and 80% respectively.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.4
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• pp.36-44
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• 2012

Electrical impedance tomography is a relatively new imaging modality in which the internal conductivity (or resistivity) distribution of a object is reconstructed based on the injected currents and measured voltages through the electrodes placed on the surface of the object. In this paper, it is assumed that the relationship between the resistivity distribution and the resistance of electrodes is linear. From this linear relation, the weighting matrix can be obtained and modified iterative Landweber method is applied to estimate the internal resistivity distribution. Additionally, to accelerate the convergence rate and improve the spatial resolution of the reconstructed image, optimal step lengths for the iterative Landweber method are computed from the objective function in the least-square sense. The numerical experiments have been performed to illustrate the superior reconstruction performance of the proposed scheme.