• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.973-976
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• 2006

In this paper, the inorganic multi-layer encapsulation of thin film was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter, inorganic multi-layer thin-film encapsulation was deposited onto the Ethylene Terephthalate(PET) and their interface properties between inorganic and organic layer were investigated. In this investigation, the SiON $SiO_2$ and parylene layer showed the most suitable properties. Under these conditions, the water vapor transmission rate (WVTR) for PET can be reduced from level of $0.57g/m^2/day$ (bare substrate) to $1^{\ast}10^{-5}g/m^2/day$ after application of a SiON and $SiO_2$ layer. These results indicate that the $PET/SiO_2/SiON/Parylene$ barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.920-923
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• 2003

We fabricated composite materials as a pellet structure with the various kinds of inorganic material powder. The composite materials were deposited onto the plastic film by the electron beam evaporation and water vapor transmission rates (WVTRs) were measured by the MOCON facility. As a result of WVTRs, the composite materials had lower WVTR value than any other inorganic materials. So, these films were proposed to protect the organic light emitting device (OLED) from moisture and oxygen. We can consider that the composite thin-film is one of the more suitable candidates for the thin-film passivation layer in the OLED. And, we are processing the XRD, XPS and EPMA to analyze the property of the composite material. We will also analyze properties of the current-voltage and luminescence for lifetime both the composite thin-film passivated OLED and non-passivated OLED.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.13-17
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• 2002

Ga$_2$O$_3$ nanomaterials were synthesized from mechanically ground GaN powders with thermal annealing Ga$_2$O$_3$ nanobelts were farmed in a nitrogen atmosphere, while Ga$_2$O$_3$ nanoparticles were formed inan oxygen atmosphere. The structural properties of the Ga$_2$O$_3$ nanomaterials were investigated by X-ray diffractometer (XRD) and high-resolution transmission eleotron microscope (HRTEM). The study of field emission scanning electron microscopy (FESEM) on the microstructures of nanomaterials revealed that the nanobelts are with the range of about 10∼200nm width and 10∼50nm thickness, and that nanoparticles are with the range of about 20∼50nm radius. On the basis of XRD and HRTEM data, we determined that the nanobelts grow toward a direction perpendicular to the (010) lattice plane and that they are enclosed by facets of the (10T) and (101) lattice planes. The formation of the nanobelts may be described by the vapor-solid(VS) mechanism, and the supersaturation device of gaseous phase may play an important role in the formation of Ga$_2$O$_3$ nanomaterials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1033-1036
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• 2004

Si nanocrystallites thin films on p-type (100) Si substrate have been fabricated by pulsed laser deposition using a Nd:YAG laser. After deposition, samples were annealed at the temperatures of 400 to $800^{\circ}C$. Hydrogen passivation was then performed in the forming gas (95% $N_2$ + 5% $H_2$) for 1 hr. Strong violet-indigo photoluminescence has been observed at room temperature from nitrogen ambient-annealed Si nanocrystallites. The variation of photoluminescence (PL) Properties of Si nanocrystallites thin films has been investigated depending on annealing temperatures with hydrogen passivation. From the results of PL, Fourier transform infrared (FTIR), and high-resolution transmission electron microscopy (HRTEM) measurements, it is observed that the origin of violet-indigo PL from the nanocrystalline silicon in the silicon oxide film is related to the quantum size effect of Si nanocrystallites and oxygen vacancies in the SiOx(x : 1.6-1.8) matrix affects the emission intensity.

• Transactions on Electrical and Electronic Materials
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• 제8권1호
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• pp.36-40
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• 2007

Inorganic layers, such as SiOxNy and SiOx deposited using plasma sublimation method, were tested as passivation layer for organic thin-film-transistors (OTFTs). OTFTs with bottom-gate and bottom-contact structure were fabricated using pentacene as organic semiconductor and an organic gate insulator. SiOxNy layer gave little change in characteristics of OTFTs, but SiOx layer degraded the performance of OTFTs severely. Inferior barrier properties related to its lower film density, higher water vapor transmission rate (WVTR) and damage due to process environment of oxygen of SiOx film could explain these results. Polyurea and polyvinyl acetates (PVA) were tested as organic passivation layers also. PVA showed good properties as a buffer layer to reduce the damage come from the vacuum deposition process of upper passivation layers. From these results, a multilayer structure with upper SiOxNy film and lower PVA film is expected to be a superior passivation layer for OTFTs.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1979-1984
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• 2014

We have developed an efficient method to generate highly active Pd and PdO nanoparticles (NPs) dispersed on graphene and graphene oxide (GO) by an impregnation method combined with thermal treatments in $H_2$ and $O_2$ gas flows, respectively. The Pd NPs supported on graphene (Pd/G) and the PdO NPs supported on GO (PdO/GO) demonstrated excellent carbon-carbon cross-coupling reactions under a solvent-free, environmentally-friendly condition. The morphological and chemical structures of PdO/GO and Pd/G were fully characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). We found that the remarkable reactivity of the Pd/G and PdO/GO catalysts toward the cross-coupling reaction is attributed to the high degree of dispersion of the Pd and PdO NPs while the oxidative states of Pd and the oxygen functionalities of graphene oxide are not critical for their catalytic performance.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.260-267
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• 1998

A homogeneous and stoichimetric fine powder of the ferroelectric $Pb_[0.97}La_{0.02}(Zr_{0.64}Sn_{0.25}Ti_{0.11})O_3$ (PLZST) has been prepared by the hydroxide coprecipitation method. Studies on the crystallization behavior of precursor as a function of temperature by X-ray powder diffraction and transmission electron microscopy technique were consistent with the formation of the pyrochlore phase from amorphous, initially at low temperatures around 500~$550^{\circ}C$. Further heat treatment up to $750^{\circ}C$ resulted in development of the perovskite phase with no significant pyrochlore crystallite growth. At intermediate temperatures the precursor yields a fine mixture of pyrochlore and perovskite phases. When the pyrochlore phase was heat teated in air, slight weight increase was observed in the temperature range of 300~$700^{\circ}C$, which is thought to be caused from oxygen absorption. In argon atmosphere, weight increase was not observed. On the other hand, weight loss began to occur near $700^{\circ}C$, with giving off mostly CO2 gas. This implies that the pyrochlore phase seems to be crystallorgraphycally and thermodynamically metastable. An apparent activation energy of 53.9 ㎉/mol was estimated for the pyrochlore-perovskite phase transformation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.95-95
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• 2010

An apparatus for generating flames and more particularly the microwave plasma burner for generating high-temperature large-volume plasma flame was presented. The plasma burner was composed of micvrowave transmission lines, a field applicator, discharge tube, coal and gas supply systems, and a reactor. The plasma burner is operated by injecting coal powders into a 2.45 GHz microwave plasma torch and by mixing the resultant gaseous hydrogen and carbon compounds with plasma-forming gas. We in this work used air, oxygen, steam, and their mixtures as a discharge gas or oxidant gas. The microwave plasma torch can instantaneously vaporize and decompose the hydrogen and carbon containing fuels. It was observed that the flame volume of the burner was more than 50 times that of the torch plasma. The preliminary experiments were carried out by measuring the temperature profiles of flames along the radial and axial directions. We also investigated the characteristics for coal combustion and gasification by analyzing the byproducts from the exit of reactor. As expected, various byproducts such as hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, etc. were detected. It is expected that such burner cab be applied to coal gasification, hydrocarbon reforming, industrial boiler of power plants, etc.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.234.2-234.2
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• 2014

Organic light emitting diode (OLED) is considered as the next generation flat panel displays due to its advantages of low power consumption, fast response time, broad viewing angle and flexibility. For the flexible application, it is essential to develop thin film encapsulation (TFE) to protect oxidation of organic materials from oxidative species such as oxygen and water vapor [1]. In many TFE research, the inorganic film by atomic layer deposition (ALD) process demonstrated a good barrier property. However, extremely low throughput of ALD process is considered as a major weakness for industrial application. Recently, there has been developed a high throughput ALD, called 'spatial ALD' [2]. In spatial ALD, the precursors and reactant gases are supplied continuously in same chamber, but they are separated physically using a purge gas streams to prevent mixing of the precursors and reactant gases. In this study, the $Al_2O_3$ thin film was deposited by spatial ALD process. We characterized various process variables in the spatial ALD such as temperature, scanning speed, and chemical compositions. Water vapor transmission rate (WVTR) was determined by calcium resistance test and less than $10-^3g/m^2{\cdot}day$ was achieved. The samples were analyzed by x-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM).

• 한국표면공학회지
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• 제47권4호
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• pp.181-185
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• 2014

We investigated the structural, electrical and optical characteristics of IGZO thin films deposited by a room-temperature RF reactive magnetron sputtering. The thin films deposited were annealed for 2 hours at various temperatures of 300, 400, 500 and $600^{\circ}C$ and analyzed by using X-ray diffractometer, transmission electron microscopy, atomic force microscope and Hall effects measurement system. The films annealed at $600^{\circ}C$ were found to be crystallized and their surface roughness was decreased from 0.73 nm to 0.67 nm. According to XPS measurements, concentration of oxygen vacancies were decreased at $600^{\circ}C$. Optical band gap were increased to 3.31eV. The carrier concentration and Hall mobility were sharply increased at 600oC. Our results indicate that the IGZO films deposited at a room temperature can show better thin film properties through a heat treatment.