• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.2
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• pp.109-124
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• 2023

For decades, sputtering as a physical vapor deposition (PVD) method has been a widely used technique for film coating processes. The sputtering enables oxides, metals, alloys, nitrides, etc to be deposited on a wide variety of substrates from silicon wafers to polymer substrates. Meanwhile, transparent conductive oxides (TCOs) have played important roles as electrodes in electrical applications such as displays, sensors, solar cells, and thin-film transistors. TCO films fabricated through a sputtering process have a higher quality leading to an improved device performance than other films prepared with other methods. In this review, we discuss the mechanism of sputtering deposition and detail the TCO materials. Related technologies (processing conditions, materials, and applications) are introduced for electrical applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.2
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• pp.85-89
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• 2018

In this study, functional transparent conducting layers were investigated for Si-based photoelectric applications. Double transparent conductive oxide (TCO) films were deposited on a Si substrate in the sequence of indium tin oxide (ITO) followed by aluminum-doped zinc oxide (AZO). First, we observed that the conductivity and transparency of AZO dominate the overall performance of the double TCO layers. Secondly, the double layered TCO film (consisting of AZO/ITO) deposited by sputtering was compared to a AZO-only film in terms of their optical and electrical properties. We prepared three different AZO films: ITO:3min/AZO:10min, ITO:5min/AZO:7min, and ITO:7min/AZO:4min. The results show that the optical properties (transmittance, absorbance, and reflection) can be controlled by the film composition. This may provide a significant pathway for the manipulation of the optical and electrical properties of photoelectric devices.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.297-297
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• 2010

Transparent conductive Oxide (TCO) is an essential material in the various optoelectronic applications as a transparent electrode, such as solar cells, flat panel displays and organic light emitting diodes. Currently, Indium tin oxide (ITO) is commonly used in industry due to its low electrical resistivity, high transmittance and high adhesion to substrate. However, ITO is expensive and should be prepared at high temperature, which makes it hard to use ITO in flexible devices. In this regard, Ga-doped ZnO is expected as an ideal candidate for replacing ITO.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1044-1048
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• 2007

With development of electronic products the demands for miniaturization and weight-lightening have increased until a recent date. Accordingly, The effort to substitute glass substrates was widely made. However, polymer substrates have weak point that substrates were damaged at high temperature. In this paper, we deposited transparent conductive film at low temperature. And we inserted Au thin film between oxide to compensate for deteriorated electrical characteristics. Ga-doped ZnO(GZO) multilayer coatings were deposited on glass substrate by DC sputtering. The optimization of deposition conditions of both AZO and Au layers were performed to obtain better electrical and optical characteristics in advance. We presumed that the properties of multilayer were affected by the deposition process of both GZO and Au layers. The best multilayer coating exhibited the resistivity of $2.72{\times}10^{-3}\;{\Omega}-cm$ and transmittance of 77 %. From these results, we can confirm a possibility of the application as transparent conductive electrodes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.55-60
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• 2018

Transparent conductive thin films (TCFs) are essential materials for solar cells, organic light-emitting diodes, and display panels. Indium tin oxide (ITO) is one of the most widely used commercial materials to create TCFs'; however, new materials that can possibly replace ITO at a lower cost and/or those possessing mechanical flexibility are urgently needed. Silver nanowire (AgNW) is one of those promising materials, as it is less expensive and possesses superior mechanical flexibility as compared to ITO. We used AgNW and sol-gel ZnO to fabricate composite thin films by spray coating. We propose two spray-coating methods: the 'metal-organic chemical vapor deposition (MOCVD)/AgNW' method and the Mixture method. These two methods are expected to be commercialized for high-quality and low-cost products, respectively.

• Korean Journal of Materials Research
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• v.27 no.12
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• pp.695-698
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• 2017

ZnMgBeGaO/Ag/ZnMgBeGaO multilayer structures were sputter grown and characterized in detail. Results indicated that the electrical properties of the ZnMgBeGaO films were significantly improved by inserting an Ag layer with proper thickness (~ 10 nm). Structures with thicker Ag films showed much lower optical transmission, although the electrical conductivity was further improved. It was also observed that the electrical properties of the multilayer structure were sizably improved by annealing in vacuum (~35 % at $300^{\circ}C$). The optimum ZnMgBeGaO(20nm)/Ag(10nm)/ZnMgBeGaO(20nm) structure exhibited an electrical resistivity of ${\sim}2.6{\times}10^{-5}{\Omega}cm$ (after annealing), energy bandgap of ~3.75 eV, and optical transmittance of 65 % ~ 95 % over the visible wavelength range, representing a significant improvement in characteristics versus previously reported transparent conductive materials.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.100-104
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• 2019

The 'ITO/Ag/ITO' multilayers as a highly conductive and transparent electrode, even with the optimum thickness conditions, the transmittances were much lower than those of a single ITO layer on some ranges of the visible wavelength. In order to improve the transmittance, Ag layer was formed with mesh structure. Where, the thickness of the Ag layer was about 10 nm and the space between the Ag lines was varied from 2.9 ㎛ to 19.6 ㎛ with the fixed Ag width of about 1.2 ㎛ in order to vary an open ratio of the Ag mesh structure. The transmittance and sheet resistance in the ITO/Mesh-Ag/ITO multilayer structure were analyzed depending on the open ratio. As a result, a trade off in the open ratio was necessary in order to obtain the transmittance as high as possible and the sheet resistance as possible low. By the open ratio of about 86%, in the ITO/Mesh-Ag/ITO multilayer structure, the transmittance was nearly same as the single ITO layer and the sheet resistance was about 62.3 Ω/.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.394-397
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• 2012

In this work, we studied the influence of the dopant elements concentration on the properties of SnO2 thin films deposited by pulsed laser deposition. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Hall effect measurement and UV-Vis studies were performed to characterize the deposited films. XRD results showed that the films had polycrystalline nature with tetragonal rutile structure. FE-SEM micrographs revealed that the as deposited films composed of dense microstructures with uniform grain size distribution. All the films show n-type conduction and the best transparent conductive oxide (TCO) performance was obtained on 6 wt% Sb2O5 doped SnO2 film prepared at pO2 of 60mtorr and Ts of 500 ℃. Its resitivity, optical transmittance, figure of merit are 7.8 × 10-4 Ω cm, 85% and 1.2 × 10-2 Ω-1, respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.124-124
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• 1999