• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.203-204
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• 2009

The Indium Zinc Tin Oxide (IZTO) thin films for flexible display electrode were deposited on poly carbonate (PC) and polyethersulfone(PES) and glass substrates at room temperature by facing targets sputtering (FTS). Two different kinds of targets were installed on FTS system. One is ITO ($In_2O_3$ 90 wt.%, $SnO_2$ 10 wt.%), the other is IZO ($In_2O_3$ 90 wt.%, ZnO 10 wt.%). As-deposited IZTO thin films were investigated by a UV/VIS spectrometer, an X-ray diffractometer (XRD), an atomic force microscope (AFM) and a Hall Effect measurement system. As a result, we could prepare the IZTO thin films with the resistivity of under $10^{-4}\;[{\Omega}{\cdot}cm]$ and IZTO thin films deposited on glass substrate showed an average transmittance over 80% in visible range (400~800 nm) in all IZTO thin films except in IZTO thin film deposited at $O_2$ gas flow rate of 0.1[sccm].

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.221-226
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• 1990

The solvolysis of substitued phenacyl tosylates was studied in binary solvent mixtures of methanol-acetonitrile and methanol-acetone at 55$^{\circ}C$. Except for m-nitrophenacyl tosylate, the rate constants were increased with both of electron-donating substituents and electron-withdrawing ones and its rate constants were the largest in the binary solvent mixtures of 90% MeOH-10% MeCN. The results show that the reactions were changed with dissociative $S_N2$ mechanism judging from the magnitude of 1/m values going from the electron-withdrawing group to the electron-donating one of the substrate. And above results were consisted with the account for the PES model and QM approach.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.15-20
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• 2010

In this study, AZO (Al: 3 wt%) thin films have been prepared on PES Plastic substrates at various working pressure (5~20 mTorr), $O_2$ gas flow rate(0~3%) and the fixed substrate temperature of 200 f by using the RF magnetron sputtering and their optical and electrical properties have been studied. The XRD measurement shows that AZO thin films exhibit c-axis preferred orientation. From the results of AFM measurements, it is known that the lowest surface roughness (3.49 nm) is obtained for the AZO thin film fabricated at 5 mTorr of working pressure and 3% of $O_2$ gas flow rate. The optical transmittance of AZO thin films is measured as 80% in the visible region. We observe that the energy band gap of AZO thin films increases with decreasing the working pressure and the $O_2$ gas flow rate. This phenomenon is due to the Burstein-Moss effect. Hall measurement shows that the maximum carrier concentration ($2.63\;{\times}\;10^{20}\;cm^{-3}$) and the minimum resistivity ($4.35\;{\times}\;10^{-3}\;{\Omega}cm$) are obtained for the AZO thin film fabricated at 5mTorr of working pressure and 0% of $O_2$ gas flow rate.

• Journal of the Korean Vacuum Society
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• v.19 no.6
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• pp.495-500
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• 2010

In this study, $Al_2O_3$ and $TiO_2$ films was deposited on to PES (poly(ethersulfon) substrate by using atomic layer deposition as functions of deposition temperature and plasma power. The density and carbon contents of $Al_2O_3$ and $TiO_2$ films was changed by varying process conditions. High density thin films was achieved through optimizing the process conditions. Buffer layer was deposited prior to the processing of upper thin films to avoid PES surface destruction during the high power plasma process and to enhances the tortuous path for water vapor permeation for the defect decoupling effect. The water vapor transmission rate by using MOCON test was investigated to analyze the effect. Water vaper permeation properties was improved by using the inorganic multi-layer passivation layer and activation energy of the water vapor permeation was increased.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.5
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• pp.387-391
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• 2012

Graphene was fabricated onto Ni/Si substrate using a rapid-thermal pulse CVD and they were transferred onto the Ti/PES flexible substrate. For top electrode applications of the BMNO dielectric films, graphene was patterned using a argon plasma. Through an AFM image and a leakage current density of the BMNO films grown onto various bottom electrodes before and after bending test, BMNO films grown onto the graphene bottom electrode showed no change of the microstructure and the leakage current density after the bend.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.214-215
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• 2008

Zinc-oxide(ZnO) films were deposited on PC(polycarboanate) and PES(polyethersulphone) substrates by using RF(radio-frequency)sputter with various rf sputtering Power at a room temperature. The effects of rf sputtering Power on the structural and optical properties of ZnO films were investigated by using atomic force microscopy, X-ray diffraction, and UV spectrophotometer. The most excellent structural and properties of a ZnO film are obtained in the condition of an rf-power of 150 W. This film shows larger Grain size and lower surface roughness and a higher optical transmittance of over 80 % in the visible range than other films deposited in the different conditions of rf- power. Regardless of substrate types, The presence of a strong diffraction peak indicates that films have a (0 0 2) preferred orientation associated with the hexagonal phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.173-176
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• 2005

Teijin사의 HT100-B60의 폴리카보네이트(polycarbonate) $100{\mu}m$, I-Component사의 PES(polyethersulfone) $200{\mu}m$, Ferrania사의 PAR(polyacrylate) $100{\mu}m$와 $200{\mu}m$를 사용하였다 열팽창계수의 차이로 인해 공정상 기판의 가열과 냉각시 열응력이 발생하여 기판의 크랙발생의 원인이 된다. 이를 최소화하기 위해 모든 공정이 시작하기 전에 pre-annealing을 통해 plastic 기판의 시간별 공정을 실시하였다. plastic film의 annealing time은 0h, 12h, 24, 40h, 50h, 60h, 70h, 80h으로 사간을 달리하여 오븐 안의 진공상태를 조성하여 실험하였다. Thermal evaporator로 Al을 약 170nm 증착하였으며 (주)동진 세미캠의 DTFR-1011s DR LCD용 감광액을 Spin Coating Spread(500rpm/6sec), Spin(3000rpm/20sec)으로 coating하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.339-339
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• 2010

The metallic nanoparticles (Pt, Au, Ag. Cu, etc.) supported on ceria-titania mixed oxide exhibit a high catalytic activity for the water gas shift reaction ($H_2O\;+\;CO\;{\leftrightarrow}\;H_2\;+\;CO_2$) and the CO oxidation ($O_2\;+\;2CO\;{\leftrightarrow}\;2CO_2$). It has been speculated that the high catalytic activity is related to the easy exchange of the oxidation states of ceria ($Ce^{3+}$ and $Ce^{4+}$) on titania, but very little is known about the ceria titanium interaction, the growth mode of metal on ceria titania complex, and the reaction mechanism. In this work, the growth of $CeO_x$ and Au/$CeO_x$ on rutile $TiO_2$(110) have been investigated by Scanning Tunneling Microscopy (STM), Photoelectron Spectroscopy (PES), and DFT calculation. In the $CeO_x/TiO_2$(110) systems, the titania substrate imposes on the ceria nanoparticles non-typical coordination modes, favoring a $Ce^{3+}$ oxidation state and enhancing their chemical activity. The deposition of metal on a $CeO_x/TiO_2$(110) substrate generates much smaller nanoparticles with an extremely high activity. We proposed a mechanism that there is a strong coupling of the chemical properties of the admetal and the mixed-metal oxide: The adsorption and dissociation of water probably take place on the oxide, CO adsorbs on the admetal nanoparticles, and all subsequent reaction steps occur at the oxide-admetal interface.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1443-1444
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• 2011

플렉시블 OLED 소자에서 주요한 역할을 하는 기판은 디스플레이의 성능, 신뢰성과 가격을 결정한다. 플렉시블 OLED소자의 기판으로는 PET, PC, PES, PEN과 같은 고분자 계열의 기판이 많이 사용되고 있지만 거칠기 등의 문제가 있는 것으로 알려져 있다. 본 논문에서는 셀룰로오스 종이를 사용하는 투명 플렉시블 OLED 소자를 개발하였다. 본 논문에서는 개발한 셀룰로오스 종이의 표면 거칠기는 $3.1{\AA}$이었으며, 투과도는 97.6%로서 PET기판 보다 우수한 특성을 보여주었다. 셀룰로오스 종이를 기판위에 양극으로 Ni을 이용하는 녹색 발광 플렉시블 OLED소자를 구현하였다.