• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1526-1529
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• 2005

Zinc oxide films have been actively investigated as transparent electrode materials for display. We report the effect of the working pressures on electro-optical properties of Al-doped ZnO thin films deposited by d.c. magnetron sputtering. The resistivity of the ZnO thin films was depended on atomic bombardment effect by working pressure.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.543-544
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• 2006

Pentacene thin film transistors fabricated without photolithographic patterning were fabricated on the plastic substrates. Both the organic/inorganic thin films and metallic electrode were patterned by shifting the position of the shadow mask which accompanies the substrate throughout the deposition process. By using an optically transparent zirconium oxide ($ZrO_2$) as a gate insulator and octadecyltrimethoxysilane (OTMS) as an organic molecule for self-assembled monolayer (SAM) to increase the adhesion between the plastic substrate and gate insulator and the mobility with surface treatment, high-performance transistor with field effect mobility $.66\;cm^2$/V s and $I_{on}/I_{off}$>$10^5$ was formed on the plastic substrate. This technique will be applicable to all structure deposited at low temperature and suitable for an easy process for flexible display.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.383-384
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• 2008

$SnO_2$ oxides are considerable interest for the development of transparent electrode, thin film resistor and gas sensors. Electrospinning is a class of nanofiber forming processes by which electrostatic forces are employed to control the production of nanofibers. In this study, antimony doped tin oxide thin films were prepared by electrospinning process. Effects of ATO doping concentration and applied voltage on electrical and light transmission properties were investigated.

• Journal of the Korean Ceramic Society
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• v.37 no.11
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• pp.1025-1032
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• 2000

산화분위기에서의 반응성 이온빔 스퍼터링법으로 Sn과 Sb 금속 타겟을 사용하여 실온에서 ATO 박막을 증착하였다. Sb 첨가량, 박막의 두께 및 열처리가 ATO 박막의 전기적 특성과 광학적 특성에 미치는 효과를 연구하고자 하였다. 제조된 ATO 박막의 두께는 약 1500$\AA$과 1000$\AA$으로 조절하였으며, Sb 농도는 10.8wt% 또는 14.9wt%임이 XPS 분석에 의하여 확인되었다. 증착한 박막의 열처리는 40$0^{\circ}C$~$600^{\circ}C$의 온도범위에서 산소 또는 forming gas(10% H$_2$-90% Ar) 분위기에서 30분간 수행하였다. 이렇게 제조된 ATO 박막은 Sb의 첨가량, 두께 및 열처리 조건에 따라 다양한 전기 비저항 값과 가시광선 대역에서의 광투과도를 나타내었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.446-447
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• 2007

Aluminisum-doped zinc oxide (AZO) films are attractive materials as transparent conductive electrode because they are inexpensive, nontoxic and abundant element compared with indium tin oxide (ITO). In our paper, AZO films have been deposited on glass (coming 1737) substrates by RF magnetron sputtering. The AZO film was post-annealed at $600^{\circ}C$, $800^{\circ}C$ for 2 hr with $N_2$ atmosphere, respectively. We investigated that the electric properties and qualitative analysis of AZO films, which measured using the methods of Hall effect, X-ray photoelectron spectroscopy (XPS).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.65-66
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• 2006

Solubility of single wall carbon nanotubes (SWNTs) has been determined in various dispersing media by using the solvent parameters such as Kamlet-Taft parameter and 3-dimensional parameters. Nitric acid-treated SWNTs exhibit significantly improved solubility in hydrogen bondable solvents as well as in solvent mixtures. The forming bucky gel with ionic liquid allows for the new group of dissolving solvent. The dissolution behavior of SWNTs provides a route for SWNT dispersion/exfoliation in preparing electrically conductive films such as transparent electrode.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.57-60
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• 2009

Transparent electrode ZnO:Al(AZO)films were deposited on a PES (polyethersulfone) polymer substrate for thin film solar cells applications. A PES substrate with a thickness of 0.2mm and transmittance > 90% in the visible range was used because it is light weight and can deform easily. AZO thin films were prepared at a fixed DC power, $PO_2\;=\;P(O_2)/[P(O_2)\;+\;P(Ar)]$, and various substrate temperatures. The properties of AZO thin films were examined by X-ray diffraction, UV/VIS spectroscopy, four-point probe, Hall measurements, and field emission scanning electron microscopy. The lowest resistivity of all the films was $4.493\;{\times}\;10^{-4}\;[\Omega-cm]$ and the transmittance was > 80% in the visible range.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.2
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• pp.31-34
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• 2018

In this study, the feasibility of ZnO/Al/ZnO flexible transparent electrodes for future flexible optoelectronic devices was investigated. All depositions were performed on PET substrates. The thicknesses of the top and bottom ZnO layers were 5-70 nm and 2.5-20 nm, respectively. The highest visible light transmittance was recorded when the thicknesses of the top and bottom ZnO layers 30 nm and 2.5 nm, respectively. 62% optical transmittance (at the wavelength of 400 nm) and sheet resistance of $19{\Omega}/{\Box}$ were measured. After repetitive bending test at a curvature radius of 5 mm, the transmittance and sheet resistance did not change.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.73-76
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• 2020

Silver nanowires (AgNWs) intrinsically possess high conductivity, ductility, and network structure percolated in a low density, which have led to many advanced applications of transparent and flexible electronics. Most of these applications require patterning of AgNWs, for which photolithographic and printing-based techniques have been widely used. However, several drawbacks such as high cost and complexity of the process disturb its practical application with patterning AgNWs. Herein, we propose a novel method for the patterning of AgNWs by employing UV-curable adhesive tape with a structure of liner/adhesive layer/polyolefin (PO) film and UV irradiation to simplify the process. First, the UV-curable adhesive tape was attached to AgNWs/polyurethane (PU), and then selectively exposed to UV irradiation by using a photomask. Subsequently, the UV-curable adhesive tape was peeled off and consequently AgNWs were patterned on PU substrate. This facile method is expected to be applicable to the fabrication of a variety of low-cost, shape-deformable transparent and wearable devices.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.993-994
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• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.