• Electrical & Electronic Materials
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• v.29 no.4
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• pp.12-21
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• 2016

• The Magazine of the IEIE
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• v.7 no.4
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• pp.52-62
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• 1980

• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.36.1-36.1
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• 2004

• Electrical & Electronic Materials
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• v.24 no.9
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• pp.3-11
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• 2011

• Electrical & Electronic Materials
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• v.11 no.7
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• pp.631-636
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• 1998

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.52-56
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• 2001

The Breakdown electric field of ZnO semiconductor devices in voltage-current characteristics was increased by increasing of additive materials. The specimen that has not additive materials was not formed spinel structure. The critical voltage that has not spinel structure was 235[V]. When the additive materials has 0.5 and 2[mol%], the Breakdown electric field was 840 and 758[V] in each additive materials. The Breakdown electric field of varistors as a factor of voltage and current was increased by addition of oxide antimony. The varistors that has oxide antimony was linearly increased in low electric field.

• Electrical & Electronic Materials
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• v.3 no.1
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• pp.1-8
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• 1990

본 논문에서는 TiO$_{2}$첨가함량이 ZnO바리스터의 미세구조에 미치는 영양에 대해 검토하였다. 실험결과, TiO$_{2}$ 첨가함량이 증가함에 따라 ZnO 결정립의 평균크기는 점차적으로 감소하였으며 스피넬상은 증가하였다. 그리고 TiO$_{2}$ 첨가에 의해 ZnO 결정립은 불균일하게 이상형으로 거대 성장되었으며 첨가함량 증가에 따라 거래 성장된 결정립의 크기도 증가하였다. 또한 TiO$_{2}$ 첨가함량 증가에 따라 파괴전압이 저하하였으며 이는 ZnO 입자의 평균크기가 증가하기 때문인 것을 확인할 수 있었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.969-974
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• 1998

The effects of $La_2O_3$on the microstructure and electrical characteristics of Pr-based ZnO varistors were investigated. The average grain size increased in the range of 21.9~56.3$\mu$ m with increasing $La_2O_3$additive content(0.0~2.0 mol%). La was, of course grain boundary, largely segregated at the nodal point. As $La_2O_3$additive content increases, threshold voltage and nonlinear coefficient decreased and leakage current increased. In particular, 2.0 mol% $La_2O_3$-added varistor exhibited low threshold voltage 17.0V/mm and nonlinear coefficient of about 6. Based on these results, this varistor can be said to be used as low-voltage varistor, if nonlinear coefficient is somewhat improved forward.

• Electrical & Electronic Materials
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• v.9 no.10
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• pp.1019-1026
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• 1996

In this study, we may be presented the carrier oscillation properties for the low-voltage varistor fabricated by a new method of three composition seed grain, in order to analyze the behavior of carriers at the its equivalent circuit model. The oscillation phenomena of carriers appeared from current-voltage characteristics under knee voltage is shown by the transient flow of nontrapped carriers group in the trap level of intergranular layer, surface state and/or depletion layer. In particularly, current oscillation phenomena is hardly shown in the high electric field. It is that the injected carriers from both electrodes are directly from the conduction band of forward biased ZnO grain through the intergranular layer into the reverse biased ZnO grain, because the trap level in the electric field above the knee voltage is mostly filled.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.857-860
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• 2000

The objective of this paper is to demonstrate degradation phenomena through DC degradation tests and predicts degradation phenomena as a function of time from the tests. The ZnO varistor used in this investigation were fabricated by standard ceramic techniques. Especial, these were sintered in nitrogen atmosphere, at 2 h, for $1300^{\circ}C$. The conditions of DC degradation test were 115$\pm$$2^{\circ}C$for 0, 2, 4, and 8 h, respectively. To demonstrate the degradation phenomena of ZnO varistors, Voltagecurrent analyses were performed before and after the degradation test, and frequency analyses were used with the time of the degradation tests. It was found that the degradation occurred in not grain but grain boundary and the degradation behavior of varistors was unsymmetrically degraded with the direction of tests.