• Geophysics and Geophysical Exploration
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• v.6 no.3
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• pp.143-152
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• 2003

Among the various geophysical approaches to identify the leakage of leachate with conductivity variation, conventional electrical resistivity survey has been mainly used at waste landfill. We adopted small-loop electromagnetic (EM) survey using multi-frequencies in parallel with electrical resistivity survey to delineate the leakage of leachate through the shallow soil layer at a waste landfill in Jeju Island, and also with self-potential monitoring to detect the streaming potential produced by the movement of leachate. There were no evidences of leakage from waste landfill according to the results of the electrical resistivity survey and SP monitoring, and it was also true from the results of water quality analysis at stream around waste landfill periodically. On the other hand, the results of one-dimensional inversion of spatially-filtered small-loop EM survey data showed the anomalous zone of low resistivity with depth both around and inner waste landfill.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.358-358
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• 2012

The application of BZO (Boron-doped Zinc Oxide) films use as the TCO(Transparent Conductive Oxide) material for display and solar cell industries, where the conductivity of the BZO films plays a critical role for improvement of cell performance. Thin BZO films are deposited on glass substrates by using RF sputter system. Then charging flow rates of O2 gas from zero to 10 sccm, thereby controlling the impurity concentration of BZO. BZO deposited on soda lime glass and RF power was 300 W, frequency was 13.56 MHz, and working pressure was $5.0{\times}10-6$ Torr. The Substrate and glass between distance 200 mm. We measured resistivity, conductivity, mobility by hall measurement system. Optical properties measured by photo voltaic device analysis system. We measured surface build according to oxygen flow rate from XPS (X-ray Photoelectron Spectroscopy) system. The profile of the energy distribution of the electrons emitted from BZO films by the Auger neutralization is measured and rescaled so that Auger self-convolution arises, revealing the detail structure of the valence band. It may be observed coefficient ${\gamma}$ of the secondary electron emission from BZO by using ${\gamma}$-FIB (Gamma-Focused Ion Beam) system. We observed the change in electrical conductivity by correlation of the valence band structure. Therefore one of the key issues in BZO films may be the valence band that detail structure dominates performance of solar cell devices. Demonstrating the secondary electron emission by the Auger neutralization of ions is useful for the determination of the characteristics of BZO films for solar cell and display developments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.100-105
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• 1995

Bulk glasses in the system $Na_2O$-CaO-$Al_2O_3$-$B_2O_3$-$SiO_2$ containing 20 to 30 mol% sod-ium hav been subjected to a sodium silver ion-exchange reaction for 0, 24, 36, 48 jr were analysed by electrical characterization Ion-exchanged glasses exhibit resistivity and activation energy values lower than those of the untreated ones. The electrical conductivity increase with sodium content and ion-exchanged time. In this experiment the electrical conductivity exhibit a maximum value of 1.78${\times}$10$^{-4}$S/cm at $200^{\circ}C$ which contains 30 mol% sodium and subjects ion-exchange reaction for 48hr.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.175-175
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• 2010

Transparent conducting oxide (TCO) films are widely used as transparent conducting thin film material for application in various fields such as solar cells, optoelectronic devices, heat mirrors and gas sensors, etc. Recently the increased utilization of many transparent electrodes has accelerated the development of inexpensive TCO materials. Indium tin oxide (ITO) film is well-known for TCO materials because of its low resistivity, but there is disadvantage that it is too expensive. ZnO film is cheaper than ITO but it shows thermally poor stability. On the contrary, antimony-doped tin oxide films (ATO) are more stable than TCO films such as Al-doped zinc oxide (AZO) and ITO. Moreover, SnO2 film shows the best thermal and chemical stability, low cost and mechanical durability except the poor conductivity. However, annealing is proved to improve the conductivity of ATO film. Therefore, in this work, antimony (6 wt%) doped tin oxide films to improve the conductivity were deposited on 7059 corning glass by RF magnetron sputtering method for the application to transparent electrodes. In general, of all TCO films, glass is the most commonly selected substrate. However, for future development in flexible devices, glass is limited by its intrinsic inflexibility. In this study, we report the growth and properties of antimony doped tin oxide (ATO) films deposited on PES flexible substrate by using RF magnetron sputtering. The optimization process was performed varying the sputtering parameters, such as RF power and working pressure, and parameter effect on the structural, electrical and optical properties of the ATO films were investigated.

• Journal of the Korean institute of surface engineering
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• v.48 no.4
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• pp.158-162
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• 2015

To substitute indium tin oxide (ITO), many substituents have been studied such as metal nanowires, carbon based materials, 2D materials, and conducting polymers. These materials are not good enough to apply to an electrode because theses exhibit relatively high resistance. So metal grids are required as an additionalelectrode to improve the conductivities of substituents. The metal grids were printed by electrohydrodynamic printing system using Ag nanoparticle based ink. The Ag grids showed high uniformity and the line width was about $10{\mu}m$. The Ag nanoparticles are surrounded by dispersants such as unimolecular and polymer to prevent aggregation between Ag nanoparticles. The dispersants lead to low conductivity of Ag grids. Thus, the sintering process of Ag nanoparticles is strongly recommended to remove dispersants and connect each nanoparticles. For sintering process, the interface and microstructure of the Ag grid were controlled in 1.0 torr Ar atmosphere at aound $400^{\circ}C$ of temperature. From the sintering process, the uniformity of the Ag grid was improved and the defects on the Ag grids were reduced. As a result, the resistivity of Ag grid was greatly reduced up to $5.03({\pm}0.10){\times}10^{-6}{\Omega}{\cdot}cm$. The metal grids embedded substrates containing low pressure Ar sintered Ag grids showed 90.4% of transmittance in visible range with $0.43{\Omega}/{\square}$ of sheet resistance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.6
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• pp.603-608
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• 2023

Carbon black with high purity and excellent conductivity is used as a conductive filler in the semiconductive compound for EHV (Extra High Voltage) power cables of 345 kV or higher. When carbon black and CNT (carbon nanotube) are applied together as a conductive filler of a semiconductive compound, stable electrical properties of the semiconductive compound can be maintained even though the amount of conductive filler is significantly reduced. In EHV power cables, since the semi-conductive layer is close to the conductor, stable electrical characteristics are required even under high-temperature conditions caused by heat generated from the conductor. In this study, the theoretical principle that a semiconductive compound applied with carbon black and CNT can maintain excellent electrical properties even under high-temperature conditions was studied. Basically, the conductive fillers dispersed in the matrix form an electrical network. The base polymer and the matrix of the composite, expands by heat under high temperature conditions. Because of this, the electrical network connected by the conductive fillers is weakened. In particular, since the conductive filler has high thermal conductivity, the semiconductive compound causes more thermal expansion. Therefore, the effect of CNT as a conductive filler on the thermal conductivity, thermal expansion coefficient, and volume resistivity of the semiconductive compound was studied. From this result, thermal expansion and composition of the electrical network under high temperature conditions are explained.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.77-79
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• 2008

Polynitro fullerenes were synthesized by reaction C-60 in benzen solution with a mixture of NaNO$_2$ and HNO$_3$. Hydrolysis of polynitro fullerenes in aqueous NaOH gave the corresponding polyhydroxylated fullerenes. Sulfonation reaction was carried out in pyridine solution of ClSO$_3$H. Infrared spectra of the resultant fullerene derivatives showed the characteristic IR bands, corresponding to absorptions of O-H, N-O, and SO$_3$Na functions. Electric resistivity and thermal transmittance of wool fiber absorbed with the water-soluble C-60 were investigated. Thermal transmittances of wool fiber were increased with increasing water-soluble C-60 concentrations, but electric conductivity were decreased with raising water-soluble C-60 uptake values.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.1010-1017
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• 2011

The use of plated front contact for metallization of silicon solar cell may alternative technologies as a screen printed and silver paste contact. This technologies should allow the formation of contact with low contact resistivity a high line conductivity and also reduction of shading losses. A selective emitter structure with highly dopes regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing. When fabricated Ni/Cu plating metallization cell with a selective emitter structure, it has been shown that efficiencies of up to 18% have been achieved using this technology.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.93-96
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• 2017

The structural, electrical and optical properties of Ti thin films fabricated by dual magnetron sputtering were investigated under various film thicknesses. The fabricated Ti thin films exhibited uniform surfaces, crystallinity, various grain sizes, and with various film thicknesses. Also, the crystallinity and grain size of the Ti thin films increased with the increase of film thickness. The electrical properties of Ti thin films improved with the increase of film thickness. The results showed that the performance of TCO-less DSSC critically depended on the film thickness of the Ti working electrodes, due to the conductivity of Ti thin film. However, the maximum conversion efficiency of TCO-less DSSC was exhibited at the condition of 100 nm thickness due to the surface scattering of photons caused by the variation of grain size.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.9
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• pp.1013-1020
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• 1992

The conductivity variation of a high resistivity bulk silicon semiconductor, whose electrodes were deposited with aluminum vapor, was studied experimentally by measuring the X-ray intensity and current flow, which was developed by X-ray radiation while applying a pulse voltage to the silicon, in a load resistor connected to the semiconductor. The current flow observed immediately as the X-ray radiated, and when the X-ray decreased. It was found from the observation of switching current for the X-ray intensity and the voltage applied in the semiconductor that the switching current of the semiconductor increased as the intensity of the X-ray and the applied voltage increased. In case of lower applied voltage, the switching current for higher applied voltage depended on the intensity of the X-ray radiated due to the saturation of electron and hole.