• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.968-971
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• 2002

Hole injection characteristics have been investigated with various metal anodes such as Ni, Pt, Cu, and AI for the top emission polymer light emitting diodes (PLEDs). Devices were composed of metal anode, Poly(3,4-ethylenedioxythiophene) doped with polystyrene sultponated acid (PEDT:PSS), poly [2-methoxy-5-(2-ethylhexyoxy)-1,4-phenylene-vinylene] (MEH-PPV) and Al cathode. The hole injection from ITO anode has been also investigated for the comparison. The I-V characteristics of the PLEDs with different metal anodes were measured. The work function of the anode is strongly related to the hole injection of the device. The current density of the device with Ni anode with higher work function was higher than that of the device with ITO or AI anode at the same operating voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.792-796
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• 2002

In this work, porous silicon(PS) layer is used as a sensing material to detect organic gases. To do this, PS sensors with membrane structure are fabricated. The sensors were made by applying the technologies of membrane formation by anisotropic etching of silicon, and PS layer formation by anodization in HF solution. From fabricated sensors, current-voltage (I-V) curves were measured against ethanol (called alcohol), methanol and acetone gases evaporated from 0.1 to 0.5% solution concentrations at $36^{\circ}C$. As the result, all curves showed rectifying behavior due to a diode structure between Si and PS, and the conductance of sensor devices increased largely with the organic solution concentration at high voltage of 5V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.739-742
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• 2002

This paper described on the fabrication of microstructures by DRIE(deep reactive ion etching). SOI(Si-on-insulator) electric devices with buried cavities are fabricated by SDB technology and electrochemical etch-stop. The cavity was fabricated the upper handling wafer by Si anisotropic etch technique. SDB process was performed to seal the fabricated cavity under vacuum condition at -760 mmHg. In the SDB process, captured air and moisture inside of the cavities were removed by making channels towards outside. After annealing($1000^{\circ}C$, 60 min.), The SDB SOI structure was thinned by electrochemical etch-stop. Finally, it was fabricated microstructures by DRIE as well as an accurate thickness control and a good flatness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.678-681
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• 2002

In this paper, Characterization for several 3-D embedded passive elements with different structures was performed. The equivalent circuit optimization for embedded inductor was performed by HSPICE simulation software. After extracting each parameter values, the difference of parameter from each structure was examined. From this work, effective characterization of passive devices with similar structure will be possible.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.50-53
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• 2001

The thermoelectric refrigeration technologies have no moving parts. compressor, or piping required. In this study, the basic capacity of thermoelectric devices and development on some thermoelectric refrigerator were reviewed and basic technical concepts related with many kinds of thermoelectric materials were discussed. Especially the result of performance test on thermoelectric refrigerator whose minimum temperature of $-2^{\circ}C$ was introduced briefly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1050-1053
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• 2002

This paper presents metal structure that is fabricated using UV-LIGA process with PMER N-CA3000. In order to fabricate metal structure with high aspect ratio, the systematic optimization method was adopted and then the structure of $36{\mu}m$ thick mold with aspect ratio 7:1 (trench) and $32{\mu}m$ thick nickel structure was obtained. This structure is applied to the fabrication of optical switch.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.980-983
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• 2002

We investigated the effect of quinolate metal complex layer as an electron injection layer on the performance of OLEDs and optimized the device efficiency by varying from 0.5 to 10nm thickness of Liq layer. OLED with a structure of indium tin oxide/$\alpha$-napthylphenylbiphenyl(NPB,40nm)/tris-(8-hydroxyquinoline)aluminum(Alq3, 50nm)/Aluminum(150nm) were fabricated in sequence. The device with 1nm Quinolate metal complex layer showed significant enhancement of the device performance.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.18-20
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• 2005

최근 송배전 시스템 분야에서 종래의 인간의 개입을 최소화하여 이루어질 수 있도록 통합화, 자동화 및 원격 감시화가 추진되고 있으며 이는 기존의 전기 장비들을 통신 기능을 갖는 마이크로 프로세스 기반의 IED(Intelligent Electronic Device)로 대체함으로써 가능해 졌다. 단일 표준화 작업이 이루어지기 전 다양한 프로토콜의 사용에 따른 장비 간 호환성 결여로 통신 프로토콜 표준화 필요성이 강하게 제기되었고, 1990년대 표준화 작업을 시작하여 최근 변전소 자동화용 단일 세계 표준인 IEC 61850이 UCA2.0과 유럽의 경험을 기반으로 IEC주관아래 개발되었다. 이러한 세계기술 동향을 반영해 IEC 61850 기반의 종합변전소 자동화 시스템의 구축이 필요하고, 이에 따라 본 논문에서는 IEC 61850 통신 프로토콜을 살펴보고 기본적인 IED 통신 실험 장치를 구성하고 메시지 전송 실험을 수행하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.324-325
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• 2006

In order to develop high efficiency white organic light-emitting diodes (OLEDs), OLED devices consisted of red and blue emitting layers (EMLs) were fabricated and the effect of respective layer thickness and the order of layer stacking on the luminous efficiency was evaluated Red/blue structure showed higher efficiency than blue/red, due to the higher exiton formation. In the blue layer of red/blue structure. However, the efficiency of the red/blue significantly depended on the thickness of the red layer, whereas the thickness of the blue layer was not affect so much. The optimum thickness of the red layer was 20 ${\AA}$, where the luminous and power efficiencies were 155 cd/A and 10.51 lm/W at 1000~3000$cd/m^2$ respectively and the maximum luminance was about 80,000 $cd/m^2$.

• Transactions on Electrical and Electronic Materials
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• v.16 no.5
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• pp.290-292
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• 2015

We have reported about bipolar resistive switching effect on Poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]:Graphene oxide composite films, which are sandwiched between aluminum and indium tin oxide electrodes. In this case, I-V sweep curve showed a hysteretic behavior, which varied according to the polarity of the applied voltage bias. The device exhibited excellent switching characteristics, with the ON/OFF ratio being approximately two orders in magnitude. The device had good endurance (10⁵ cycles without degradation) and long retention time (5 × 10³ s) at room temperature. The bistable switching behavior varied according to the trapping and de-trapping of charges on GO sites; the carrier transport was described using the space-charge-limited current (SCLC) model.