• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.200-200
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• 2010

이 논문에서는 field-effect mobility를 향상시키기 위해 triple-layer (SiNx/SiO2/SiOxNy stack 구조)를 gate dielectric material 로 LTPS TFTs에 적용하였다. 이는 플라즈마 처리 기법과 적층구조의 효과적인 in-situ 공정을 이용하여 interface trap과 mobile charge를 낮추어 높은 이동도의 결과를 생각하고 실험하였다. 실험은 SiO2 gatedielectric과 triple-gate dielectric의 C-V curve를 1 MHz의 주파수에서 측정하였다. 또한 Transfer characteristics를 single SiO2 gatedielectric과 triple-gate dielectric of SiNx/SiO2/SiOxNy를 STA 장비를 이용해 측정하였다. 위의 측정을 통해 threshold voltage, mobility, subtheshold swing, driving current, ON/OFF current ratio를 비교 분석하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.317-317
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• 2011

Water dissociation on oxide surface has been researched in many fields because of its importance as fundamental phenomenas. MgO(001) is a good model system to understand heterogeneous catalysis, gas sensors, ground-water contaminants, and atmosphere chemistry. Over decades, ultrathin film of MgO on Ag(100) have attracted research activities thanks to its enhanced catalytic property. Correlation of the oxide and the metal, potential screening, charge fluctuation from interface reconstruction makes different energetics of hydroxylation of waters on film. We calculate the water-spliting energetics under the vacuum system.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.383-383
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• 2011

We fabricated thermal annealing-free polymer solar cells (PSC) by processing with additive and applied to flexible substrates. The 1, 8-Diiodooctane of 3 vol% blended with active solution resulted in enhancement of $J_{SC}$ due to increase of light absorption and hole mobility as improving the crystallinity of P3HT. In addition, the $V_{OC}$ of PSCs with additive was improved by inserting $TiO_2$ layer without any treatment. The $TiO_2$ layer prevented the direct contact between active layer and Al electrode and reduced the charge recombination near Active/Al interface. It was confirmed by calculation of J0 and photo-voltage transient measurement. The power conversion efficiencies of annealing-free PSCs using additive for ITO glass and flexible (ITO PEN) substrate were obtained 3.03% and 2.45%, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.647-651
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• 2001

The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were applied to Weibull distribution probability. First of all, speaking of dielectric breakdown properties, the more hardener increased, the stronger breakdown strength became at low temperature because of cross-linked density by the virtue of ester radical. The breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised and the electric filed is concentrated. In the case of filled specimens with treating silane, the breakdown strength become much higher. Finally, from the analysis of weibull distribution, it was confirmed that to low allowed breakdown probability under 0,.1%, the applied field value needed to be under 21.5MV/cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.413-416
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• 1996

The ceramic dielectrics were fabricated by mixing of Mn $O_2$ and ZnO at (B $a_{0.85}$ $Ca_{0.15}$)Ti $O_3$ and studied for dielectric relaxation characteristics. The dielectric relaxation time was increased by space charge polarization of palaelectric layer at the low temperature and frequency but it was decreased by Interface polarization at the high temperature and frequency. The remnant polarization and coercive field of ceramic dielectrics was decreased by rising temperature.ure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.260-264
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• 1996

In this study, the dieiectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability . As a result. first of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature, and the breakdown strength of specimens because it is believed that the adding filler farms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. In the case of filled specimens with treating silane, the breakdown strength become much higher since the suggests that silane coupling agent improves interfacial combination and relays electric field concentration. Finally, from the analysis 7f weibull distribution. it was confirmed that as the allowed breakdown probability was given by 0.11[%].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.159-163
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• 2003

In this study, the DC dielectric breakdown of epoxy composites used for PCB material was experimented and then its data were simulated by Weibull distribution equation. The more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical, and the breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. From the analysis of Weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1[%], the applied field value needed to be under 21.5[kV/mm].

• Journal of Applied Reliability
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• v.13 no.2
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• pp.129-140
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• 2013

As a fundamental experimental study for reliability improvement of lithium ion secondary battery, degradation mechanism was investigated by microscopic observation and acoustic emission monitoring. Microstructural observation of the decomposed battery after cycle test revealed mechanical and chemical damages such as interface delamination, microcrack of the electrodes, and solid electrolyte interphase (SEI). Acoustic emission (AE) signal was detected during charge and discharge of lithium ion battery to investigate relationships among cumulative count, discharge capacity, and microdamages. With increasing number of cycle, discharge capacity was decreased and AE cumulative count was observed to increase. Observed damages were attributed to sources of the detected AE signals.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.138-139
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• 2013

본 연구는 ZnO-TFT 소자에 Hf의 첨가에 따른 소자 특성 및 게이트 바이어스 스트레스에 대한 특성에 대해 분석을 하였다. Hf-Zn-O 박막은 Hf의 조성이 증가함에 따라 작아지는 grain size로 인해 TFT 소자의 전계효과 이동도와 게이트 바이어스 스트레스에서의 문턱전압의 변화가 더 커지는 것을 확인하였다. 한편, Hf이 14at% 함유된 HZO-TFT에서는 이동도는 현저히 저하되었지만, 게이트 바이어스 스트레스에서의 문턱전압의 변화가 현저히 개선되는 것을 확인하였는데, 이는 Hf의 조성이 증가함에 따라 비정질화 되어 grain boundaries에 의한 trap의 영향이 줄어든 결과를 확인하였다. 또한, 전계효과 이동도와 소자의 안정성을 확보하기 위해, poly-ZnO와 amorphous-HZO로 구성된 다중층 채널 구조를 이용한 TFT소자에서는 전계효과 이동도과 소자의 안정성이 개선된 결과를 보였다. 이는 채널과 게이트 산화물의 interface charge trap의 감소와 back-channel effect가 감소한 결과임을 확인하였다.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.174-177
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• 2003

Electric double-layer capacitors based on charge storage at the interface between a high surface area activated carbon electrode and an electrolyte solution are characterized by their long cycle-life and high power density in comparison with batteries. However, energy density of electric double-layer capacitors obtained at present is about 6 Wh/kg at a power density of 500W/kg which is smaller as compared with that of batteries and limits the wide spread use of the capacitors. Therefore, a new capacitor that shows larger energy density than that of electric double-layer capacitors is proposed. The new capacitor is the hybrid capacitor consisting of activated carbon cathode, carbonaceous anode and an organic electrolyte. Maximum voltage applicable to the cell is over 4.2V that is larger than that of the electric double-layer capacitor. As a result, discharged energy density on the basis of stacked volume of electrode, current collector and separator is more than 18Wh/l at a power density of 500W/l.