• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• The monthly packaging world
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• 통권361호
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• pp.65-69
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• 2023

• Carbon letters
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• 제14권4호
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• pp.247-250
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• 2013

In this study, we present a facile method of fabricating graphene oxide (GO) films on the surface of polyimide (PI) via layer-by-layer (LBL) assembly of charged GO. The positively charged amino-phenyl functionalized GO (APGO) is alternatively complexed with the negatively charged GO through an electrostatic LBL assembly process. Furthermore, we investigated the water vapor transmission rate and oxygen transmission rate of the prepared (reduced GO $[rGO]/rAPGO)_{10}$ deposited PI film (rGO/rAPGO/PI) and pure PI film. The water vapor transmission rate of the GO and APGO-coated PI composite film was increased due to the intrinsically hydrophilic property of the charged composite films. However, the oxygen transmission rate was decreased from 220 to 78 $cm^3/m^2{\cdot}day{\cdot}atm$, due to the barrier effect of the graphene films on the PI surface. Since the proposed method allows for large-scale production of graphene films, it is considered to have potential for utilization in various applications.

• Journal of Sensor Science and Technology
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• 제16권6호
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• pp.434-440
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• 2007

Two kinds of new NOx sensing mechanism was proposed and examined. One of those was potentiomtric sensor based on the measurement of decomposed oxygen from NO using YSZ porous diffusion barrier and Pd catalytic electrode. The sensor based on decomposed oxygen measurement responded to the range of 300 - 1000 ppm NO in $N_{2}$ environment and the sensitivities were coincident with theoretical values at 700 and $800^{\circ}C$ but the decomposition rate depended on gas flow rate. The other sensor was equilibrium potentiometric type using $Gd_{2}O_{3}$-nitrates solid solution as sensing material. The sensor using $Gd_{2}O_{3}$-nitrates solid solution was suitable for NOxxsensing at $700^{\circ}C$ in 5 % oxygen and the sensitivity was 19.3 mV/decade. However, long term stability of the sensing material at high temperature was not sufficient.

• Applied Chemistry for Engineering
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• 제22권3호
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• pp.261-265
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• 2011

The sterilization effects of atmospheric pressure plasma with the mixture of argon and oxygen were analyzed. The plasma reactor with the shape of dielectric barrier discharge produced the uniform distribution of glow discharge and generated ozone gas effectively according to the various process parameters. The sterilization for E. coli was affected by power, oxygen ratio in the mixture gas, treatment time and distance between reactor and sample. The concentration of ozone was a major source for the sterilization of E. coli, which was enhanced by the increase of power and oxygen ratio. In this study, the effect of atmospheric pressure plasma treatment for the sterilization was confirmed and its result can deliver the atmospheric pressure plasma treatment as the novel sterilization method instead of conventional methods.

• Journal of the Korean Graphic Arts Communication Society
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• 제7권1호
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• pp.16-30
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• 1989

The anodixed aluminium film by sulfuric acid - method has many pores, the inner, called barrier layers, is active. They have strong absorption of dye. on be other, the absorption of dye is lost by Sealing, the surface is not dyed. We make IMAGE FORMATION on the film by the chemical behavior. This study made sure whether ion absorption is not in the barrier layer by IRRS and ESCA, considerated the mechanism of inage formation.

• Journal of the Korean Institute of Telematics and Electronics A
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• 제30A권7호
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• pp.47-59
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• 1993

The thermal stability of "stuffed" TiN/Ti barrier matals with different annealing history has been studied to improve the contact reliability of Al/Si contacts in 16M DRAM. The annealing conditions before the Al deposition such as film thickness, the annealing temperature and the annealing ambient have been varied. For TiN(900A)/Ti(300A) annealed at 450 in nitrogen ambient to form a "stuffed barrier" by inducing oxygen atoms into grain boundaries, there is no observation of Al penetrations into Si substrates after the post heat treatment of up to 700 even though there are massive amounts of Al found in TiN film after the post heat treatment of 600 indicating that TiN has a "sponge-like" function due to its ability to absorb several amounts of aluminum at elevated temperature. The TiN/Ti diffusion barrier annealed at 550 has, however, failed after the post heat treatment at 600. The thinner diffusion barriers with TiN(300A)/Ti(100A) failed after the post heat treatment at 600.he post heat treatment at 600.

• Korean Journal of Environmental Biology
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• 제40권4호
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• pp.641-650
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• 2022

The purpose of this study was to compare the efficiency of air and oxygen injected into the underwater non-thermal dielectric barrier discharge plasma (DBD plasma) device used to remove five types of antibiotics (tetracycline, doxycycline, oxytetracycline, clindamycin, and erythromycin) artificially contained in the fish farm discharge water. The voltage given to generate DBD plasma was 27.8 kV, and the measurement intervals were 0, 0.5, 1, 2, 4, 8, 16 and 32 minutes. Tetracycline antibiotics significantly decreased in 4 minutes when air was injected and were reduced in 30 seconds when oxygen was injected. After the introduction of air and oxygen at 32 minutes, 78.1% and 95.8% of tetracycline were removed, 77.1% and 96.3% of doxycycline were removed, and 77.1% and 95.5% of oxytetracycline were removed, respectively. In air and oxygen, 59.6% and 83.0% of clindamycin and 53.3% and 74.3% of erythromycin were removed, respectively. The two antibiotics showed lower removal efficiency than tetracyclines. In conclusion, fish farm discharge water contains five different types of antibiotics that can be reduced using underwater DBD plasma, and oxygen gas injection outperformed air in terms of removal efficiency.

• Journal of Environmental Science International
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• 제22권12호
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• pp.1561-1569
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• 2013

This study carried out a laboratory scale plasma reactor about the characteristics of chemically oxidative species (${\cdot}OH$, $H_2O_2$ and $O_3$) produced in dielectric barrier discharge plasma. It was studied the influence of various parameters such as gas type, $1^{st}$ voltage, oxygen flow rate, electric conductivity and pH of solution for the generation of the oxidant. $H_2O_2$ and $O_3$.) $H_2O_2$ and $O_3$ was measured by direct assay using absorption spectrophotometry. OH radical was measured indirectly by measuring the degradation of the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical). The experimental results showed that the effect of influent gases on RNO degradation was ranked in the following order: oxygen > air >> argon. The optimum $1^{st}$ voltage for RNO degradation were 90 V. As the increased of $1^{st}$ voltage, generated $H_2O_2$ and $O_3$ concentration were increased. The intensity of the UV light emitted from oxygen-plasma discharge was lower than that of the sun light. The generated hydrogen peroxide concentration and ozone concentration was not high. Therefore it is suggested that the main mechanism of oxidation of the oxygen-plasma process is OH radical. The conductivity of the solution did not affected the generation of oxidative species. The higher pH, the lower $H_2O_2$ and $O_3$ generation were observed. However, RNO degradation was not varied with the change of the solution pH.

• Proceedings of the Korean Magnestics Society Conference
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• 한국자기학회 2011년도 자성 및 자성재료 국제학술대회
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• pp.14-14
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• 2011

Limited understanding of the surface properties of $Pt_3Ni$ for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cell (PEMFC) has motivated the study of magnetic properties and electronic structures of Pt segregated $Pt_3Ni$ (111) surface during adsorption of oxygen molecule on it. The first principle method based on density functional theory (DFT) is carried out. Nonmagnetic Pt has induced magnetic moment due to strong hybridization between Ni 3d and Pt 5d. It is found that an oxygen molecule prefers bridge site with Pt rich subsurface environment for adsorption on the surface of Pt segregated $Pt_3Ni$ (111). It is seen that there is very small charge transfer from $O_2$ to Pt. The curve of energy versus magnetic moment of the oxygen explains the magnetic moments in transition states. We found the dissociation barrier of 1.07eV significantly higher than dissociation barrier 0.77eV on Pt (111) suggesting that the dissociation is more difficult on Pt segregated $Pt_3Ni$ (111) surface. The spin polarized densities of states are presented in order to understand electronic structures of Pt and $O_2$ during the adsorption in detail.