• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.62-68
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• 2009

In this paper, we investigate a new method to measure the thickness of thin transparent objects utilizing a step index multi-mode optical fiber sensor. The method mainly depends on the refraction rate of transparent target, the diameter of optical fibers and the distance to reflector. We confirmed the effects of these parameters through the experimental verification tests. The comparison between the theoretical vs. analytical results shows good agreements with each other. The proposed model also enables users to measure the thickness of thin transparent objects without considering the reflection from the target. This approach provides simple, cost-effective and non-contact solutions to measure the thickness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.510-514
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• 1997

The thin film that is electrically conductive and optically transparent is called conductive transparent thin film. ITO(Indium-Tin Oxide) which is a kind of conductive transparent thin film has been widely used in solar cell, transparent electrical heater, selective optical filter, FDP(Flat Display Panel) such as LCD(Liquid Crystal Display), PDP(Plasma Display Panel) and so on. Especially in PDP, ITO films is used as a transparent electrode in order to maintain discharge and decrease consumption power through the improvement of cell structure. In this study, we prepared ITO by reactive r.f. sputtering with indium-tin(Sn 10wt%) alloy target instead of indium-tin oxide target. The ITO films deposited at low temperature 15$0^{\circ}C$ and 8% $O_2$. Partial pressure showed about 3.6 Ω/$\square$. At the end of firing, the resistance of ITO was decreased, the optical transparence was improved above 90%.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1411-1413
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• 1997

The thin film that is electrically conductive and optically transparent is called conductive transparent thin film. ITO(Indium-Tin Oxide) which is a kind of conductive transparent thin film has been widely used in solar cell, transparent electrical heater, selective optical filter, FDP(Flat Display Panel) such as LCD (Liquid Crystal Display), PDP(Plasma Display Panel) and so on. Especially in PDP, ITO films is used as a transparent electrode in order to maintain discharge and decrease consumption power through the improvement of cell structure. In this study, we prepared ITO by reactive r.f. sputtering with indium-tin(Sn wt 10%) alloy target instead of indium-tin oxide target. The ITO films deposited at low temperature $150^{\circ}C$ and 8% $O_2$ partial pressure showed about $3.6{\Omega}/{\square}$. At the end of firing, the resistance of ITO was decreased, the optical transparence was improved above 90%.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.316-316
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• 2014

Two different transparent conducting oxide (TCO) layers of Al-doped ZnO (AZO) and $WO_3$ were prepared by a rf sputtering process. Working pressure, deposition time, and target-to-substrate distance were varied for the sputtering process to improve electrical properties of the resulting layer. Thickness of the TCO layers was measured by a profile meter of ${\alpha}$-step. To evaluate the electrical conductivity, surface resistivity of the TCO layers was measured by a four-point probe technique. Decrease of the working pressure resulted in increase of deposition rate and decrease of surface resistivity of the resulting layer. Increase of the layer thickness due to increased deposition time resulted in decrease of surface resistivity of the resulting layer. The shorter the target-to-substrate distance was, the lower was the surface resistivity of the resulting layer.

• Korean Journal of Materials Research
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• v.26 no.4
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• pp.222-227
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• 2016

Tin oxides have been studied for various applications such as gas detecting materials, transparent electrodes, transparent devices, and solar cells. p-type SnO is a promising transparent oxide semiconductor because of its high optical transparency and excellent electrical properties. In this study, we fabricated p-type SnO thin film using rf magnetron sputtering with an SnO/Sn composite target; we examined the effects of various oxygen flow rates on the SnO thin films. We fundamentally investigated the structural, optical, and electrical properties of the p-type SnO thin films utilizing X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis spectrometry, and Hall Effect measurement. A p-type SnO thin film of $P_{O2}=3%$ was obtained with > 80% transmittance, carrier concentration of $1.12{\times}10^{18}cm^{-3}$, and mobility of $1.18cm^2V^{-1}s^{-1}$. With increasing of the oxygen partial pressure, electrical conductivity transition from p-type to n-type was observed in the SnO crystal structure.

• Current Photovoltaic Research
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• v.3 no.2
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• pp.50-53
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• 2015

Indium (In) is widely used for transparent electrodes of photovoltaics as a form of indium tin oxide (ITO) due to its superior characteristics of environmental stability, relatively low electrical resistivity and high transparency to visible light. However, In has been worn off in proportion to growth the In related market, and it leads to raise of price. Although In is obtained from ITO target scarps, much harmful elements are used for the recycling process. To decrease of harmful elements, ITO swarf particles obtained from target scraps was characterized whether it is feasible to transparent conductive oxide (TCO). The ITO swarf was crushed with milling process, and it was mixed with new ITO nanoparticles. The mixed particles were well dispersed into ink solvent to make-up an ink, and it was well coated onto glass substrate. After heat-treatment at $400^{\circ}C$ under $N_2$ rich environments, optical transmittance at 550 nm and sheet resistance of the ITO ink coated layer was 71.6% and $524.67{\Omega}/{\square}$, respectively. Therefore, it was concluded that the ITO swarf was feasible to TCO of touch screen panel.

• Electrical & Electronic Materials
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• v.8 no.6
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• pp.699-707
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• 1995

The material that is both conductive in electricity and transparent to the visible ray is called transparent conducting thin film. It has many fields of application such as Solar Cell, Liquid Crystal display, Vidicon on T.V, transparent electrical heater, selective optical filter, and a optical electric device , etc. In the recent papers on several TCO( transparent conducting oxide ) material, the study is mainly focusing on ITO(indium tin oxide) because ITO shows good results on both optical and electrical properties. Nowaday, in the development of LCD(Liquid Crystal display), the low temperature process to reduce the production cost and to deposit ITO on polymer substrate (or low melting substrate) has been demanded. In this study, we prepared indium tin oxide(ITO) by a cylindrical DC magnetron sputtering with Indium-tin (9:1) alloy target instead of indium-tin oxide target. The resistivity of the film deposited in oxygen partial pressure of 5% and substrate temperature of 140.deg. C. is 1.6*10$\^$-4/.ohm..cm with 85% optical transmission in viaible ray.

• Journal of Surface Science and Engineering
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• v.50 no.2
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• pp.55-71
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• 2017

Transparent Conductive Oxide (TCO), especially Indium Tin Oxide (ITO) films are almost prepared by DC magnetron sputtering because of the advantage of obtaining homogeneous large area coatings with high reproducibility. The purpose of this report is describe a detailed investigation of key factors dominating electrical and structural properties of sputtered ITO films. It was confirmed that crystallinity and electrical properties of ITO films were strongly depend on the sputtering pressure and kinetic energy of sputtered particles which are expected to have a close relation with the transport processes between target and substrate. And also, nodule formation on the ITO target was suppressed by both $CaCO_3$ addition and decreasing micro-pore in the target. On the other hand, we focused on the characteristics of amorphous TCO film to use as transparent electrode for various applications. To realize high thermoelectric performance, it was tried to control both high electrical conductivity and low thermal conductivity for the amorphous IZO:Sn films.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.207-207
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• 2011

Amorphous transparent oxide semiconductors (a-TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). Recently, Nomura et al. demonstrated high performance amorphous IGZO (In-Ga-Zn-O) TFTs.1 Despite the amorphous structure, due to the conduction band minimum (CBM) that made of spherically extended s-orbitals of the constituent metals, an a-IGZO TFT shows high mobility.2,3 But IGZO films contain high cost rare metals. Therefore, we need to investigate the alternatives. Because Aluminum has a high bond enthalpy with oxygen atom and Alumina has a high lattice energy, we try to replace Gallium with Aluminum that is high reserve low cost material. In this study, we focused on the electrical properties of IZO:Al thin films as a channel layer of TFTs. IZO:Al were deposited on unheated non-alkali glass substrates (5 cm ${\times}$ 5 cm) by magnetron co-sputtering system with two cathodes equipped with IZO target and Al target, respectively. The sintered ceramic IZO disc (3 inch ${\phi}$, 5 mm t) and metal Al target (3 inch ${\phi}$, 5 mm t) are used for deposition. The O2 gas was used as the reactive gas to control carrier concentration and mobility. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of IZO:Al thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• Clean Technology
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• v.21 no.4
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• pp.209-216
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• 2015

Indium-Tin-Oxide (ITO) is a material that is widely used for transparent conductive electrodes (TCEs). Indium (In), chief element of the ITO, is expected to be depleted in the near future owing to its high cost and limited reserves. To overcome the issue, ITO has to be retained by recycling redundant ITO targets after manufacturing processes. In this article, we proposed an efficient recycling way of the redundant ITO targets with investigation of the current recycling tendencies in domestic and foreign countries. As a result, it was revealed that only In is recycled from the redundant targets in domestic and Japan. As well, fabrication of TCEs is being researched with ITO nanoparticles solutions. However, since the TCEs fabricated with ITO target is superior to those with other materials, it is thought that establishment of regeneration technology of ITO itself is demanded for an efficient recycling and fabrication of ITO target.