• 반도체디스플레이기술학회지
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• 제10권2호
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• pp.39-44
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• 2011

In this study, we have investigated the structural and electrical characteristics of IZO thin films deposited on flexible substrate for the OLED (organic light emitting diodes) devices. For this purpose, PES was used for flexible substrate and IZO thin films were deposited by RF magnetron sputtering under oxygen ambient gases (Ar, $Ar+O_2$) at room temperature. In order to investigate the influences of the oxygen, the flow rate of oxygen in argon mixing gas has been changed from 0.1sccm to 0.5sccm. All the samples show amorphous structure regardless of flow rate. The electrical resistivity of IZO films increased with increasing flow rate of $O_2$ under $Ar+O_2$. All the films showed the average transmittance over 85% in the visible range. The OLED device was fabricated with different IZO electrodes made by configuration of IZO/a-NPD/DPVB/$Alq_3$/LiF/Al to elucidate the performance of IZO substrate. OLED devices with the amorphous-IZO (a-IZO) anode film show better current density-voltage-luminance characteristics than that of OLED devices with the commercial crystalline-ITO (c-ITO) anode film. It can be explained that very flat surface roughness and high work function of a-IZO anode film lead to more efficient hole injection by reduction of interface barrier height between anode and organic layers. This suggests that a-IZO film is a promising anode materials substituting conventional c-ITO anode in OLED devices.

• 반도체디스플레이기술학회지
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• 제7권4호
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• pp.7-11
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• 2008

ITO (Indium Tin Oxide) thin films have been extensively studied for OLED devices because they have high transparent properties in the visible wavelength and a low electrical resistivity. These ITO films are deposited by rf-magnetron sputtering under different ambient gases (Ar, Ar+$O_2$ and Ar+$H_2$) at $300^{\circ}C$. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon has been changed from 0.5sccm to 5sccm and from 0.01sccm to 0.25sccm respectively. The resistivity of ITO film increased with increasing flow rate of $O_2$ under Ar+$O_2$ while it is nearly constant under Ar+$H_2$. And the peak of ITO films obtained (222) and (400) orientations and the average transmittance was over 80% in the visible range. The OLED device fabricated with different ITO substrates made by configuration of ITO/$\alpha$-NPD/Alq3/LiF/Al to elucidate the performance of ITO substrate for OLED device.

• 반도체디스플레이기술학회지
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• 제9권3호
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• pp.53-58
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• 2010

In this study, we have investigated the effect of the ambient gases on the characteristics of IZO thin films for the OLED (organic light emitting diodes) devices. For this purpose, IZO thin films were deposited by RF magnetron sputtering under various ambient gases (Ar, $Ar+O_2$ and $Ar+H_2$) at $150^{\circ}C$. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon mixing gas has been changed from 0.1sccm to 0.5sccm, respectively. All the samples show amorphous structure regardless of ambient gases. The electrical resistivity of IZO film increased with increasing flow rate of $O_2$ under $Ar+O_2$ while under $Ar+H_2$ atmosphere the electrical resistivity showed minimum value near 0.5sccm of $H_2$. All the films showed the average transmittance over 85% in the visible range. The OLED device was fabricated with different IZO substrates made by configuration of IZO/${\alpha}$-NPD/DPVB/$Alq_3$/LiF/Al to elucidate the performance of IZO substrate. OLED devices with the amorphous-IZO (a-IZO) anode film show better current densityvoltage-luminance characteristics than that of OLED devices with the commercial crystalline-ITO (c-ITO) anode film. It can be explained that very flat surface roughness and high work function of a-IZO anode film lead to more efficient hole injection by reduction of interface barrier height between anode and organic layers. This suggests that a-IZO film is a promising anode materials substituting conventional c-ITO anode in OLED devices.

• 한국수소및신에너지학회논문집
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• 제14권1호
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• pp.8-16
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• 2003

$TiO_2$ thin films were deposited by DC reactive magnetron sputtering with variations in sputtering parameter such as Ar and $O_2$ flow rate, DC power, substrate temperature and magnetic field. Deposition rate, crystal structure, chemical bond of $TiO_2$ films on the deposition conditions were investigated by Alpha-step, X-ray Diffractometer(XRD), X-ray Photoelectron Spectroscopy(XPS). When the DC power was applied at 500watt, deposition rate of $TiO_2$ film was about 480A/min. $TiO_2$ films coated under the deposition condition of 15sccm Ar and 7~10sccm $O_2$ flow rate was only observed anatase phase. With increasing substrate temperature from RT to $300^{\circ}C$, crystal orientation of $TiO_2$ films variously became.

• 한국세라믹학회지
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• 제34권2호
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• pp.131-138
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• 1997

희석기체로써 Ar 및 H2를 사용하여 MTS(CH3SiCl3)를 원료물질로 한 탄화규소막을 흑연 기판 위에 화학증착시켰다. 본 연구는 증착온도 130$0^{\circ}C$, 총압력은 10 torr 및 MTS와 원료 운반기체의 총유량은 100 sccm으로 일정하게한 상태에서, 각 희석기체의 첨가에 따른 성장거동의 변화를 고찰하고자 하였다. 증착속도는 희석기체와 상관없이 첨가량이 200sccm일 때 최대값을 갖는 모양을 보였으나, Ar을 첨가할 때가 H2에 비해 더 빠른 증착속도를 나타냈다. 이러한 증착속도 특성은 전체 증착속도가 물질전달 율속단계에 있을 때, 각 희석기체의 첨가에 따라 변화되는 경막 두께(boundary layer thickness) 및 원료물질 농도의 상관관계에 기인한다고 여겨졌다. 우선배향성은 Ar의 경우 모든 첨가량의 범위에서 (220)면으로 우선배향되었으나, H2의 경우에는 200sccm이상에서 첨가량에 비례하여 (111)면으로 우선배향되는 경향을 보였다. 표면미세구조는 Ar을 첨가한 경우에 일정하게 facet구조를 유지하였으나, H2의 경우에는 facet에서 평탄한(smooth)구조로 변화되었다. 표면조도의 경우 첨가량이 늘어남에 따라 지속적으로 Ar에서는 증가하였지만, H2에서는 감소하였다.

• 분석과학
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• 제30권2호
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• pp.82-88
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• 2017

Adenophorae Radix (AR) is a frequently used medicinal herb; because of its popularity, products containing similar herbal products are often sold as substitutes, especially if their morphology is similar. However, any analytical method to identify AR based on quantitative analysis is not registered in Korea, Japan and China Pharmacopoeias. This study developed a simple HPLC method to discriminate between authentic AR and substitutes. Linoleic acid was used as a marker compound of AR. Our optimized HPLC-UV conditions included a mobile phase of 90 % acetonitrile under isocratic condition, and a flow rate of 1.0 mL/min at room temperature. Detection wavelength was set at 205 nm. Linoleic acid was detected at 13.5 minutes for a total analysis time of 20 minutes. The standard herb of AR contained 0.025 % of linoleic acid, while four authentic AR samples and eight substitutes contained 0.040~0.071 % and 0.004~0.014 %, respectively. Comparison of the linoleic acid concentrations of the sample types to reference AR showed that among 12 samples, only the four samples were authentic. Thus, our HPLC-UV method, along with our suggested content criterion for linoleic acid concentration, can be used for the quick and accurate determination whether the herbal products are authentic AR or substitute.

• 방사성폐기물학회지
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• 제18권2호
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• pp.169-177
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• 2020

Here, the stability of stainless steel 316 (SS-316) was investigated to identify its applicability in the oxide reduction process, as a component in related equipment, to produce a complicated gas mixture composed of O₂ and Cl₂ under an argon (Ar) atmosphere. The effects of the mixed gas composition were investigated at flow rates of 30 mL/min O₂, 20 mL/min O₂ + 10 mL/min Cl₂, 10 mL/min O₂ + 20 mL/min Cl₂, and 30 mL/min Cl₂, each at 600℃, during a constant argon flow rate of 170 mL/min. It was found that the corrosion of SS-316 by the chlorine gas was suppressed by the presence of oxygen, while the reaction proceeded linearly with the reaction time regardless of gas composition. Surface observation results revealed an uneven surface with circular pits in the samples that were fed mixed gases. Thermodynamic calculations proposed the combination of Fe and Ni chlorination reactions as an explanation for this pit formation phenomenon. An exponential increase in the corrosion rate was observed with an increase in the reaction temperature in a range of 300 ~ 600℃ under a flow of 30 mL/min Cl₂ + 170 mL/min Ar.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.458-458
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• 2010

The process window for the etch selectivity of silicon nitride ($Si_3N_4$) layers to extreme ultra-violet (EUV) resist and variation of line edge roughness (LER) of EUV resist were investigated durin getching of $Si_3N_4$/EUV resist structure in a dual-frequency superimposed capacitive coupled plasma (DFS-CCP) etcher by varying the process parameters, such as the $CH_2F_2$ and $N_2$ gas flow rate in $CH_2F_2/N_2$/Ar plasma. The $CH_2F_2$ and $N_2$ flow rate was found to play a critical role in determining the process window for infinite etch selectivity of $Si_3N_4$/EUV resist, due to disproportionate changes in the degree of polymerization on $Si_3N_4$ and EUV resist surfaces. The preferential chemical reaction between hydrogen and carbon in the hydrofluorocarbon ($CH_xF_y$) polymer layer and the nitrogen and oxygen on the $Si_3N_4$, presumably leading to the formation of HCN, CO, and $CO_2$ etch by-products, results in a smaller steady-state hydrofluorocarbon thickness on $Si_3N_4$ and, in turn, in continuous $Si_3N_4$ etching due to enhanced $SiF_4$ formation, while the $CH_xF_y$ layer is deposited on the EUV resist surface. Also critical dimension (and line edge roughness) tend to decrease with increasing $N_2$ flow rate due to decreased degree of polymerization.

• 대한기계학회논문집B
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• 제33권6호
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• pp.418-426
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• 2009

The effect of an inertia moment of a pump flywheel on the thermal-hydraulic behaviors of the KALIMER-600(Korea Advanced LIquid MEtal Reactor) reactor pool during an early-phase of a loss of normal heat sink accident was investigated. The thermal-hydraulic analyses for a steady and a transient state were made by using the COMMIX-1AR/P code. In the present analysis a quarter of the reactor geometry was modeled in a cylindrical coordinate system, which includes a quarter of a reactor core and a UIS, a half of a DHX and a pump and a full IHX. In order to evaluate the effects of an inertia moment of the pump flywheel, a coastdown flow whose flow halving time amounts to 3.69 seconds was supplied to a natural circulation flow in the reactor vessel. Thermal-hydraulic behaviors in the reactor vessel were compared to those without the flywheel equipment. The numerical results showed a good agreement with the design values in a steady state. It was found that the inertia moment contributes to an increase in the circulation flow rate during the first 40 seconds, however to a decrease of it there after. It was also found that the flow stagnant region induced by a core exit overcooling decelerated the flow rate. The appearance of the first-peak temperature was delayed by the flow coastdown during the initial stages after a reactor trip.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.124-125
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• 2005

ZnS:Mn thin films have attracted great interest as electroluminescence devices. In this study, inductively coupled BCl$_3$/Ar plasma was used to etch ZnS:Mn thin films. We obtained the maximum etch rate of ZnS:Mn thin films was 2209 ${\AA}$/min at a BCl$_3$(20%)/Ar(80%) gas mixing ratio, an RF power of 700 W, a DC bias voltage of-250 V, a total gas flow of 20 sccm, and a chamber pressure of 1 Pa. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching products.