• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.563-567
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• 2006

Indium tin oxide (ITO) used as an electrode in organic light emitting diodes (OLEDs) and organic thin film transistors (OTFTs) was modified by a self-assembled monolayer (SAM). For device fabrication, surface of the ITO was modified by immersion in a solution including various phosphonic acid at room temperature in order to increase work function of an electrode. The work function of ITO with SAM was measured by Kelvin probe. Work function increase of 0.88 eV was observed in ITO with various SAM. Therefore, ohmic contact is achieved in an interface between ITO and organic semiconductors (pentacene). We analyzed the origin of work function increase of ITO with SAM by X-ray photoelectron spectroscopy. We confirmed that increase of oxygen bonding energy attributed to increase the work function of ITO. These results suggested that ITO with the SAM gives a high possibility for high performance of OLEDS and OTFTs.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.157-160
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• 2021

As an insulator for a thin film transistor(TFT) and an encapsulation material of organic light emitting diode(OLED), aluminum oxide (Al₂O₃) has been widely studied using several technologies. Especially, in spite of low deposition rate, atomic layer deposition (ALD) has been used as a process method of Al₂O₃ because of its low process temperature and self-limiting reaction. In the Al₂O₃ deposition by ALD method, Ar Purge had some crucial effects on the film properties. After reaction gas is injected as a formation of pulse, an inert argon(Ar) purge gas is injected for gas desorption. Therefore, the process parameter of Ar purge gas has an influence on the ALD deposited film quality. In this study, Al₂O₃ was deposited on glass substrate at a different Ar purge time and its structural characteristics were investigated and analyzed. From the results, the growth rate of Al₂O₃ was decreased as the Ar purge time increases. The surface roughness was also reduced with increasing Ar purge time. In order to obtain the high quality Al₂O₃ film, it was known that Ar purge times longer than 15 sec was necessary resulting in the self-limiting reaction.

• Journal of Magnetics
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• v.2 no.1
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• pp.22-24
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• 1997

FeN thin films were deposited by RF-reactive diode sputtering to investigate magnetic characteristics variation due to substrate tilt during the film deposition, and their magnetic properties were measured by VSM, SEM and AFM. When the substrate tilt pivot edges were parallel to the applied field, the magnetic anisotropy was increased When the substrate tilt pivot edges were perpendicular to the applied field, the easy magnetization axis became the hard magnetization axis, and the hard axis became the easy axis as the tilt angles were increased. The reason is believed to be due to the fact that the tilt induced shape magnetic anisotropy became larger than the field induced magnetic anisotropy by DC magnetic field as the crystal grains are enlongated along the substrate tilt pivot edges due to "oblique incidence anisotropy" commonly found in eveporated thin films.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1910-1912
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• 1999

This paper was described electrical characteristics of Metal/GaN contact for application of GaN thin films. The lowest contact resistivity was $1.7\times10^{-7}[\Omega-cm^2]$ at Ti/Al Structure. Mean while, GaN MESFETs have been fabricated with a 250 nm thick channel on a high resistivity GaN layer grown by GAIVBE system. For a gate-source diode reverse bias of 35 V, the gate leakage current was $120{\mu}A$. From the data, we estimate the transconductance for our GaN MESFET to be 25 mS/mm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.313-314
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• 2006

In this paper, the inorganic-organic thin film encapsulation layer was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter and Spin-Coater system, the various kinds of inorganic and organic thin-films were deposited onto the Ethylene Terephthalate(PET) and their interface properties between organic and inorganic layer were investigated Results indicates that the SiON/PI/SiON/PI/PET barrier coatings have high potential for flexible organic light-emitting diode(OLED) application.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1779-1783
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• 2006

The hybrid thin-film (HTF) passivation layer composed of the UV curable acrylate layer and MS-31 (MgO:SiO2=3:1wt%) layer was adopted in organic light emitting diode (OLED) to protect organic light emitting materials from penetrations of oxygen and water vapors. The moisture resistance of the deposited HTF layer was measured by the water vapor transmission rate (WVTR). The results showed that the HTF layer possessed a very low WVTR value of lower than $0.007g/m^2$ per day at $37.8^{\circ}C$ and 100% RH. Therefore, the HTF on the OLED was found to be very effective in protect what from the penetrations of oxygen and moisture.

• Journal of Information Display
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• v.11 no.2
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• pp.52-56
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• 2010

High-efficiency organic light-emitting diodes (OLEDs) based on multilayer transparent electrodes (MTEs) are reported. The dielectric/metal/dielectric (DMD) multilayer electrode based on a thin silver layer achieved high sheet conductance as small as $6{\Omega}/sp$ and a tuning capability in the optical and electrical properties by engineering the inner and outer dielectric layers. In the conventional normal bottom-emitting structure, a DMD-based OLED can be fabricated with 90% higher forward luminous efficiency and 30% higher external quantum efficiency (EQE) compared to ITO-based devices. Special attention was paid to the optimization method of such MTE structure considering both the injection and optical structures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.2
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• pp.45-50
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• 2022

Ga₂O₃ thin films were grown on n-type Si substrates at various growth temperatures of 500, 550, 600, 650 and 700℃. The Ga₂O₃ thin films grown at 500℃ and 550℃ were characterized as featureless flat surface. Grown at higher temperatures (600, 650, and 700℃) showed very rough surface morphology. To figure out the annealing effect on the thin films grown at relatively low temperatures (500, 550, 600, 650 and 700℃), the Ga₂O₃ films were thermally treated at 900℃ for 10 minutes. Crystal structure of the Ga₂O₃ films grown at 500 and 550℃ were changed from amorphous to polycrystalline structure with flat surface. Ga₂O₃ film grown at 550℃ was chosen for the fabrication of a Schottky barrier diode (SBD). Electrical properties of the SBDs depend on the thermal treatment were evaluated. A MSM type photodetector was made on the low temperature grown Ga₂O₃ thin film. The photocurrent for the illumination of 266 nm wavelength showed 5.32 times higher than dark current at the operating voltage of 10 V.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.2
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• pp.76-85
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• 2004

Biodevices composed of biomolecular layer have been developed in various fields such as medical diagnosis, pharmaceutical screening, electronic device, photonic device, environmental pollution detection device, and etc. The biomolecules such as protein, DNA and pigment, and cells have been used to construct the biodevices such as biomolecular diode, biostorage device, bioelectroluminescence device, protein chip, DNA chip, and cell chip. Substantial interest has focused upon thin film fabrication or the formation of biomaterials mono- or multi-layers on the solid surfaces to construct the biodevices. Based on the development of nanotechnology, nanoscale fabrication technology for biofilm has been emerged and applied to biodevices due to the various advantages such as high density immobilization and orientation control of immoblized biomolecules. This review described the nanoscale fabrication of biomolecular film and its application to bioelectronic devices and biochips.

• Journal of Information Display
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• v.11 no.1
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• pp.12-16
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• 2010

The effect of the crystallization and activated annealing of Si films using an excimer laser and the new CW blue laser are described and compared with furnace annealing for application in advanced TFTs and for future applications. Pulsed excimer laser annealing (ELA) is currently being used extensively as a low-temperature poly-silicon (LTPS) process on glass substrates as its efficiency is high in the ultra-violet (UV) region for thin Si films with thickness of 40-60 nm. ELA enables extremely low resistivity relating to high crystallinity for both the n- and p-type Si films. On the other hand, CW blue laser diode annealing (BLDA) enables the smooth Si surface to have arbitral crystal grains from micro-grains to an anisotropic huge grain structure only by controlling its power density. Both annealing techniques are expected to be applied in the future advanced TFT systems.