• 한국표면공학회지
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• 제47권3호
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• pp.104-108
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• 2014

To improve emission efficiency of organic light emitting devices (OLEDs), we fabricated the tandem OLED of ITO / 2-TNATA / NPB / SH-1: 3 vol.% BD-2 / Bphen / Liq / Al / $MoO_x$ (X nm) / 2-TNATA / NPB / SH-1: 3 vol.% BD-2 / Bphen / Liq / Al structure. And emission properties of single OLED and tandem OLED with $MoO_x$ thickness as charge generation layer (CGL) were measured. The current emission efficiency and quantum efficiency of tandem OLED with $MoO_x$ of 3 nm thickness were improved compare with single OLED from 7.46 cd/A and 5.39% to 22.57 cd/A and 11.76%, respectively. In case of thicker or thinner than $MoO_x$ of 3~5 nm, the current emission efficiency and quantum efficiency were decreased, because balance of electron and hole in emission layer was not matching. The driving voltage was increased from 8 V of single OLED to 15 V of tandem OLED by thickness increase of OLED. As a result, it was possible to improve the emission efficiency of OLEDs by optimized $MoO_x$ thickness.

• 한국진공학회지
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• 제7권s1호
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• pp.160-166
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• 1998

The field emission characteristics of defective diamond films grown by microwave plasma enhanced chemical vapor deposition (MPECVD) have been studied. X-ray diffraction, the poor crystal quality and/or small grain sizes of the diamond phase and the inclusion of the non-diamond carbon phases in these films have been condirmed by raman spectroscopy, scanning electron microscopy, atomic force microscopy, and the reflectance measurements. The degrees of the film defectiveness and the emission characteristics were dependent on the methane concentration. Current-versus-voltage measurements have demonstrated that the defective diamond films have good electron emission characteristics. characteristics strongly suggests the defect-related electron-emission mechanism. The defective diamond films deposited on Si substrates show the field emission current density of 1$\mu\textrm{A}/\textrm{cm}^2$ and 1mA/$\textrm{cm}^2$ have been measured at electric fields as low as 4.5V/$\mu\textrm{m}$ and 7.6V/$\mu\textrm{m}$, respectively. We also observed the similar emission characteristics from the defective diamond film deposited on Cr/Si substrate and could decrease the deposition temperature to $600^{\circ}C$.

• Journal of Information Display
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• 제10권1호
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• pp.45-48
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• 2009

The ionization of a helium atom was investigated as a function of gas pressure, with the use of a tungsten tip. The tungsten tip, to which the external voltage was applied, was used to generate a constant electron current. The ionization current of helium gas was measured as a function of gas pressure. Effective ionization occurred in the pressure range of 0.5-20 torr when the distance between the field emission tip and the collector was 1 cm. The ionization current was linearly proportional to the voltage that was applied to the tungsten tip.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1552-1553
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• 2006

A thermionic gun of injector linac for pohang accelerator laboratory is required to generate beam pulse width less than 1 nsec. The gun uses cathode-grid assembly(EIMAC Y824) and operates up to 80 kV anode voltage. In order research characteristics of the electron gun, emission current from gun wear measured by the wall current monitor. In this paper the pulser system and characteristics of the emission current in region from 30 mA to 15 A are described.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.887-888
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• 2003

We report the electroluminescence properties of single- and multi-layer electroluminescence devices using PtOEP phosphor. Weak emission bands with peaks at 540 and 567 nm are observed in the former and latter devices, respectively, besides the well-known 648 nm PtOEP emission. The 540 nm emission increases in proportion to the third power of current density, while the 648 nm emission band increases linearly. Discussion is made on a reason for a much smaller luminance of PtOEP compared with $Ir(ppy)_{3}$ phosphor.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.44-44
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• 2003

Free electron lasers (FEL) have, at least, the following advantages in comparison to conventional lasers： FEL can be designed for any arbitrary given emission wavelength. It is continuously tunable within wide band. Easy to get single-mode emission. Easily controlled emission structure (pulse duration, repetition rate, and pulse energy). (omitted)

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.113-117
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• 2016

Temperature dependent reverse-bias current-voltage (I-V) characteristics in Cu Schottky contacts to oxygen plasma treated n-InP were investigated. For untreated sample, current transport mechanisms at low and high temperatures were explained by thermionic emission (TE) and TE combined with barrier lowering, respectively. For plasma treated sample, experimental I-V data were explained by TE or TE combined with barrier lowering models at low and high temperatures. However, the current transport was explained by a thermionic field emission (TFE) model at intermediate temperatures. From X-ray photoemission spectroscopy (XPS) measurements, phosphorus vacancies (VP) were suggested to be generated after oxygen plasma treatment. V_P possibly involves defects contributing to the current transport at intermediate temperatures. Therefore, minimizing the generation of these defects after oxygen plasma treatment is required to reduce the reverse-bias leakage current.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.90-93
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• 1996

The conduction mechanisms of the off-current in low temperature ($\leq$600$^{\circ}C$) processed polycrystalline silicon thin film transistors (LTP poly-Si TFT's) has been systematically studied. Especially, the temperature and bias dependence of the off-current between unpassivated and passivated poly-Si TFT's was investigated and compared. The off-current of unpassivated poly-Si TFT's is due to a resistive current at low gate and drain voltage, thermal emission current at high gate, low drain voltage, and field enhanced thermal emission current in the depletion region near the drain at high gate and drain voltage. After hydrogenation, it was observed that the off-currents were remarkably reduced by plasma-hydrogenation. It was also observed that the off-currents of the passivated poly-Si TFT's are more critically dependent on temperature rather than electric field.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권8호
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• pp.577-579
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• 1999

DLC film remaining on device surface could be removed by eliminating AI sacrificial layer as a final step of lift-off process in the fabrication of DLC-coated Si-tip FEA. The field emission properties(I-V curves, hysteresis, and current fluctuation etc.) of the processed device were analyzed and the process was employed to 1.76 inch-sized FEA panel fabrication in order to evaluate its FED applicability.

• 마이크로전자및패키징학회지
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• 제6권1호
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• pp.65-73
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• 1999

Lift-off 공정에 의하여 Si-tip FEA를 제조하고 그 동작 특성을 평가하였다. 게이트 및 양극 전압에 따른 방출 전류의 변화, 최대 방출 전류, 히스테리시스 현상, MOSFET형 특성, 전류 표동, 방출된 전자에 의한 형광체 발광, 그리고 소자의 파괴 메카니즘 등이 실험 결과를 토대로 하여 폭 넓게 평가, 분석되었다.