• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.265-268
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• 1997

Electroluminescent(EL) devices are constructed using multilayer organic thin film. A cell structure of glass substrate/Indium-Tinoxide/TPD as a hole transporting layer/Alq3+Rhodamine 101 perchrolate(Red3) as an emitting layer/Alq3 as an electrron transporting layer/Al as an electrode was employed. Optimal thickness of emitting layer in EL cell was performed from the viewpoint of the electronics properties of emitting layers. The general vapor-deposition method was used to control the thickness of omitting layer in EL devices and electro-optical characteristics were measured. It is clarified that controlling thickness of emitting layer in vapor-deposition film had an effect on the change of carrier injection and EL spectrum. The intensity of red omission with luminance of 81cd/$m^2$ was achived at 11V driving voltage. The surface morphology of emitting layer in EL devices was investigated.

• Journal of the Semiconductor & Display Technology
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• v.7 no.3
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• pp.51-54
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• 2008

In this study, we investigated variations in undoped ZnO thin film properties with working pressure, $O_2$/Ar ratio, and annealing ambient. Higher vacuum pressure during deposition was observed to bring about slower growth rate resulting in samples with better crystallinity as well as hole generation efficiency through formation of shallower oxygen interstitial. Given that $O_2$/Ar ratio is greater than unity, O provided from the ambient to ZnO during annealing was found to preferably situate at interstitial sites. When He was used for the second annealing, significant changes were not observed. On the other hand, O ambient caused increased density of oxygen interstitial, thereby making the film more intrinsic-like high resistivity ZnO.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.436-437
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• 2006

The $Ag/TiO_{2-x}N_x$ nanoparticles were synthesized by photochemical deposition in a $TiO_{2-X}N_X$ suspension system. The prepared products were characterized by means of XRD, Uv-vis and photoluminescence spectra (PL). Its photocatalytic activity was investigated by the decomposition of methylene blue (MB) solution under illumination of visible and ultraviolet light, respectively. Compared to $TiO_{2-x}N_x$, the photocatalytic activity of the as-prepared $Ag/TiO_{2-x}N_x$ is obviously enhanced due to the decreasing recombination of a photoexcitated electron-hole pairs. The Mechanism in which photocatalytic activity is enhanced has been discussed in detail.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.376-382
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• 2000

We successfully fabricated OLED(Organic Light Emitting Diodes) with Al cathodes electrode deposited by the DC magnetron sputtering. The effects of a controlled Al cathode layer of an Indium Tin Oxide (ITO)/blended single polymer layer (PVK Bu:PBD:dye)/Al light emitting diodes are described. The PVK (Poly(N-vinylcarbazole)) and Bu-PBD (2-(4-biphenyl-phenyl)-1,3,4-oxadiazole) are used hole transport polymer and electron transport molecule respectively. We found that both current injection and electroluminescence output are significantly different with a variable DC sputtering power. The difference is believed to be due to the influence near the blended polymer layer/cathode interface that results from the DC power and H$\sub$2//O in a chamber. And DC sputtering deposition is an effective way to fabricate Al electrodes with pronounced orientational characteristics without damage occurring to metal-organic interface during the sputtering deposition.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.147.4-147
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• 1998

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.362-366
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• 2006

OLEDs(Organic Light Emitting Diodes) are attractive as alternative display components because of their relative merits of being self-emitting, having large intrinsic viewing angle and fast switching speed. But because of their relatively short history of development, much remains to be studied in terms of their basic device physics and design, manufacturing techniques, stability and so on. We investigated electrical properties of N, N-diphenyl-N, N bis (3-methyphenyl-l,1'-biphenyl-4,4'-diamine (TPD) and tris-8-hydroxyquinoline aluminum$(Alq_3)$ when their thicknesses were changed variedly from 3:7 to 5:5 of their thickness ratios. And we also studied properties of OLED depend on their deposition rate between $0.05{\sim}0.2$ nm/s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.275-276
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• 2005

Organic Light Emitting Diodes(OLEDs) are attractive as alternative display components because of their relative merits of being self-emitting, having large intrinsic viewing angle and fast switching speed. But because of their relatively short history of development, much remains to be studied in terms of their basic device physics and design, manufacturing techniques, stability and so on. We invested electrical properties of N,N-diphenyl-N,N bis (3-methyphenyl)-1,1'-biphenyl-4,4'-diamine(TPD) and tris-8-hydroxyquinoline aluminum($Alq_3$) when their thicknesses were changed variedly from 3:7 to 7:3 of their thickness ratios. And we also studied properties of OLEDs depend on their deposition rate between 0.05$\sim$0.2 [nm/s].

• Macromolecular Research
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• v.14 no.1
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• pp.38-44
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• 2006

Vacuum deposited copper phthalocyanine (CuPc) was placed as a thin interlayer between indium tin oxide (ITO) electrode and a hole transporting layer (HTL) in a multi-layered, organic, light-emitting diode (OLEOs). The well-stacked CuPc layer increased the stability and efficiency of the devices. Thermal annealing after CuPc deposition and magnetic field treatment during CuPc deposition were performed to obtain a stacked-CuPc layer; the former increased the stacking density of the CuPc molecules and the alignment of the CuPc film. Thermal annealing at about 100$^{circ}C$ increased the current flow through the CuPc layer by over 25$\%$. Surface roughness decreased from 4.12 to 3.65 nm and spikes were lowered at the film surface as well. However, magnetic field treatment during deposition was less effective than thermal treatment. Eventually, a higher luminescence at a given voltage was obtained when a thermally-annealed CuPc layer was placed in the present, multi-layered, ITO/CuPc/NPD/Alq3/LiF/AI devices. Thermal annealing at about 100$^{circ}C$ for 3 h produced the most efficient, multi-layered EL devices in the present study.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.353-356
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• 2014

We fabricated organic photovoltaic (OPV) based on ZnO ripple structure on indium tin oxide as electron-collecting layers and PTB7-F20 as donor polymer. In addition, atomic layer deposition (ALD) was used for preparing additional ZnO layers on rippled ZnO. Addition of 2 nm-thick ALD-ZnO resulted in enhanced initial OPV performance and stability. Based on photoluminescence results, we suggest that ALD-ZnO layers reduced number of surface defect sites on ZnO, which can act as electron-hole recombination center of OPV, and increased resistance of ZnO towards surface defect formation.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.139-145
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• 2003

This study is to propose reduction effect of scour depth and a optimum size of circular collar through experimental analyses with various collar sizes. To do so, we carried out hydraulic model experiments. In the case of with considering the collar, the effect of reduction of scour depth increased according to the increase of collar size. When size of collar is 2 as the ratio of collar diameter(W) to pier diameter(D), scour depth is decreased about 67% and deposition height is increased about 70%. The optimal size of collar proposed in this study is W/D=2 by analyzing reduction effect of scour depth, size of scour hole, and deposition height.