• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.442-444
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• 1986

• Proceedings of the KIEE Conference
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• 1984.07a
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• pp.185-187
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• 1984

• 전기의세계
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• v.29 no.2
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• pp.111-117
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• 1980

Contacts formed by vacuum evaporation of As-Te-Si-Ge chalcogenide glass onto Al metal (99.9999%) are studied by measuring paralle capacitance C(V), Cp(w), resistance R(V), Rp(w), and I-V characteristics. The fact that contact metal alloying produced high-resistance region is confirmed from the measurements of parallel capacitance and resistance. From the I-V characteristics in the pre-switcing region, it is found that electronic conduction and sitching occurs in the vicinity of metal-amorphous semiconductor interface. From the experimental obsevations, it is concuded that the current flow in the thin film is space-charge limited current (SCLC) due to the tunneling of electrons through the energy barriers.

• Progress in Superconductivity and Cryogenics
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• v.7 no.2
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• pp.39-43
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• 2005

Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 77 K should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. Recently, research and development concerning application of the conduction-cooled HTS SMES that is easily movement are actively progressing in Korea. Electrical insulation under cryogenic temperature is a key and an important element in the application of this apparatus. However, the behaviors of insulators for cryogenic conditions in air or vacuum are virtually unknown. Therefore, this work focuses on the breakdown and flashover phenomenology of dielectrics exposed in vacuum for temperatures ranging from room temperature to cryogenic temperature. Firstly, we summary the insulation factors of the magnet for HTS SMES. And a surface flashover as well as volume breakdown in air and vacuum has been investigated with two kind insulators. Finally, we will discuss applications for the HTS SMES including aging studies on model coils exposed in vacuum at cryogenic temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.209-212
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• 1995

In this paper, the $(Sr_{0.85}{\cdot}Ca_{0.15})TiO_3$ of paraelectric grain boundary layer (GBL) ceramics were fabricated. The characteristics of electrical conduction and the thermally stimulated current(TSC) were measured respectively. The region I below 200[V/cm] shows the ohmic conduction, the region II between 200[V/cm] and 1000[V/cm] can be explained by the Pool-Frenkel emission theory, and the region III above 2000[V/cm] is dominated by the tunneling effect. As a result, The origins of these peaks are that the ${\alpha}$ peak observed at $-20[^{\circ}C]$ looks like to be ascribed to the ionization excitation from donor level in the grain, and the ${\alpha}^{\prime}$ peak observed at $-20[^{\circ}C]$ appears to show up by detrap of the trapped carrier of border between the oxidation layer and the grain, and the ${\beta}$ peak observed at $80[^{\circ}C]$ seems to be resulted from hopping conduction of existing carrier in the trap site of the border between the oxidation and second phase.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.321-324
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• 1991

In this study, $(Sr{\cdot}Pb)TiO_3$ series ceramics which is used in high voltage were fabricated by the mixed oxide method, and the electrical conduction mechanism and D.C. breakdown voltage characteristics of the specimens in accordance with the contents of $Bi_2O_3{\cdot}3TiO_2$ were investigated. As a result, the leakage current was increased with the contents of $Bi_2O_3{\cdot}3TiO_2$ and the measuring temperature. At room temperature, the leakeage current was showed a tendency of saturating when D.C. electrical field of $l5{\sim}30$[kV/cm] was applied to the specimen. As a result of breakdown voltage characteristics. breakdown strength was decreased when the contents of $Bi_2O_3{\cdot}3TiO_2$ were increased. On the other hand, in the temperature region below $60[^{\circ}C]$, the electronic breakdown was occured, and in the temperature region from 60 to $200[^{\circ}C]$, the thermal breakdown was occured by the Joule heat and the dissipation factor.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1786-1790
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• 2007

The $(SrCa)TiO_3(SCT)$ thin films are deposited on Pt-coated electrode ($Pt/TiN/SiO_2/Si$) using RF sputtering method at various deposition temperature. The dielectric constant of SCT thin films were increased with the increase of deposition temperature, and changed almost linearly in temperature ranges of $-80{\sim}+90[^{\circ}C]$. Also, SCT thin films was observed the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency was observed above 200[kHz]. V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature. The conduction mechanism of the SCT thin films observed in the temperature range of $25{\sim}100[^{\circ}C]$ can be divided into three characteristic regions with different mechanism by the increasing current. The region 1 below 0.8[MV/cm] shows the ohmic conduction. The region 2 can be explained by the Child's law, and the region 3 is dominated by the tunneling effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.67-70
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• 1995

Amorpous As$\sub$10/Ge$\sub$15/Te$\sub$75/ device shows the memory switching characterisite under d.c. bias. In bulk material, a-As$\sub$10/Ge/sub15/Te$\sub$75/s switching voltage range is above 100 volts. Our purposes in this gaudy are decreasing a switching threshold voltage, finding the properties of d.c., a.c. conduction, and the characterisitics of switching threshold voltage fur a-As$\sub$10/Ge$\sub$15/Te$\sub$75/. As the results, the d.c.and a.c. conductivities increase with temperature. From the data of conductivity, various electrical and physical properties are obtained experimentally. The switching threshold voltages decrease with increasing annealing temperature and time, but increase with increasing film thickness and distance of electrode for d.c. bias.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.164-168
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• 1996

The relation between crystallinity and thermal history in low density polyethylene thin films and their effect on electric conduction phenomena and dielectric breakdown was studied. The low density polythylene thin films obtained by the solution growth method heat-treated at 140[$^{\circ}C$] for 2 h and subsequently cooling to various ways. The degree of crystallinity was estimated by the X-ray diffraction measurement for the specimen of slowly cooling, ICE quenching and liquid nitrogen quenching. The result shows that the crystallinity decreases become faster as the cooling speed increased, and that conduction phenomenon is governed by the space charge limited current in high field. It was found that the dielectric breakdown field increases with an increase in cooling speed and test number in self-healing breakdown method.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.546-549
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• 1993

The correlation between electrical conduct ion and dielectric relaxation properties of copper ion conducting glasses is discussed. The glasses were prepared in the system $CuI-Cu_2S-Cu_2O-MoO_3$ using rapid quenching technique. These glasses have high ionic conductivities at room temperature in the range of $10^{circ}$[S/m], and the conductivities increase with increasing CuI content. The activation energies for conduction are 0.26-0.57 eV. The dielectric relaxation times are 1-10uS, and the activation energy for ion jumping are 0.18-0.41eV. It is shown that the tendency of conduction properties depending on composition of the glass is similar those of dilectric relaxation.