• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.167-167
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• 2010

Indium tin oxide (ITO) has been widely used as transparent conductive oxides (TCOs) for transparent electrodes of various optoelectronic devices, such as liquid crystal displays (LCD) and organic light emitting diodes (OLED). However, indium has become increasingly expensive and rare because of its limited resources. In addition, ITO thin films have some problems for OLED and flexible displays, such as imperfect work function, chemical instability, and high deposition temperature. Therefore, multi-component TCO materials have been reported as anode materials. Among the various materials, IZTO thin films have been gained much attention as anode materials due to their high work function, good conductivity, high transparency and low deposition temperature. IZTO thin films with a thickness of 200nm were deposited on Corning glass substrate at different substrate temperature by pulsed DC magnetron sputtering with a sintered ceramic target of IZTO (In2O3 70 wt%, ZnO 15 wt%, SnO2 15 wt%). We investigated the electrical, optical, structural properties of IZTO thin films. As the substrate temperature is increased, the electrical properties of IZTO are improved. All IZTO thin films have good optical properties, which showed an average of transmittance over 80%. These IZTO thin films were used to fabricate organic light emitting diodes (OLEDs) as anode and the device performances studied. As a result, IZTO has utility value of TCO electrode although it reduced indium and we expect it is possible for the IZTO to apply to flexible display due to the low processing temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.436-437
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• 2012

염료감응형 태양전지의 성능을 향상시키기 위해서는 염료에서 여기된 전자가 TiO2 계면을 따라 TCO (Transparent Conductive Oxide)로 이동하지 않고 산화된 염료나 전해질과 재결합하는 것을 차단하는 것, 그리고 염료에 TCO의 전기적 접촉을 차단하는 것 등이 필요하다. 이를 위해 본 연구에서는 TiO2 박막층 위에 차단층 TiO2를 $450^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$에서 각각 소결한 뒤Blocking layer로서의 온도에 따른 상(phase) 변화를 통해 염료감응형 태양전지의 효율 향상에 대해 실험하였다. 기존 염료 감응형 태양전지에 대한 보고에 의하면 $600^{\circ}C$ 이상에서의 상은rutile 상임을 확인할 수 있다. 실험결과 Blocking layer로서의 TiO2를 $750^{\circ}C$에서 $750^{\circ}C$에서 sintering 했을 때, 가장 좋은 전기적 특성을 나타내었다.

• Current Photovoltaic Research
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• v.5 no.1
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• pp.28-32
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• 2017

In this paper, (Ga,Al):ZnO layers were deposited by sputtering to evaluate the device performance according to the thickness of the layer. As the thickness increased, low transmittance was observed, but the electrical resistance was improved. On the other hand, the highest efficiency was recorded at 400 nm device than a 500 nm of it. Therefore, since the critical thickness exists, it is necessary to set an adequate TCO layer thickness in consideration of the characteristics of the underlying film and the device.

• Journal of Powder Materials
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• v.14 no.1 s.60
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• pp.44-49
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• 2007

In the fabrication of dye-sensitized solar cells (DSSCs), carbon counter electrode has been tested for replacing the platinum counter electrode which has two drawbacks: limited surface area and high material cost. Poor mechanical stability of carbon layer due to weak bonding strength to electrically conductive TCO (transparent conducting oxide) glass substrate is a crucial barrier for practical application of carbon counter electrode. In the present study a carbon counter electrode with high conversion efficiency, comparable to Pt counter electrode, could be fabricated by adaption of a bonding layer between particulate carbon material and TCO substrate.

• Journal of Electrochemical Science and Technology
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• v.1 no.2
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• pp.69-74
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• 2010

Methodologies to improve photovoltaic performance of dye-sensitized solar cell (DSSC) are reviewed. DSSC is usually composed of a dye-adsorbed $TiO_2$ photoanode, a tri-iodide/iodide redox electrolyte and a Pt counter electrode. Among the photovoltaic parameters of short-circuit photocurrent density, open-circuit voltage and fill factor, short-circuit photocurrent density is the collective measure of light harvesting, charge separation and charge collection efficiencies. Internal quantum efficiency is known to reach almost 100%, which indicates that charge separation occurs without loss by recombination. Thus, light harvesting efficiency plays an important role in improvement of photocurrent. In this paper, technologies to improve light harvesting efficiency, including surface area improvement by nano-dispersion, size-dependent light scattering efficiency, bi-functional nano material, panchromatic absorption by selective positioning of three different dyes and transparent conductive oxide (TCO)-less DSSC, are introduced.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.165-168
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• 2004

In this study, AZO(ZnO:Al) thin film were prepared by FTS(Facing Target Sputtering) system. The electrical, optical and crystallographic properties of AZO thin film with $O_2$ gas flow ratio have been investigated. The thickness, transmittance, crystal structure and resistivity of AZO thin film were measured by a-step, UV-VIS spectrometer, XRD and four-point probe, respectively. As a result AZO thin film deposited with the transmittance over 80% and the resistivity about $10^{-1}\Omega-cm$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.452-452
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• 2013

ZnO is one of the most attractive transparent conductive oxide (TCO) films because of low toxicity, a wide band gap material and relatively low cost. However, the electrical conductivity of un-doped ZnO is too high to use it as TCO films in practical application. To improve electrical properties of undoped ZnO, transition metal (TM) doped ZnO films such as Al doped ZnO or Ti doped ZnO have been extensively studied. Here, we prepared Ti doped ZnO thin films by atomic layer deposition (ALD) for the application of TCO films. ALD was used to prepare Ti-doped ZnO thin films due to its inherent merits such as large area uniformity, precise composition control in multicomponent thin films, and digital thickness controllability. Also, we demonstrated that ALD method can be utilized for fabricating highly ordered freestanding nanostructures of Ti-doped ZnO thin films by combining with BCP templates, which can potentially used in the photovoltaic applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.169-174
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• 2024

In this study, the structural, electrical, and optical properties of AZO films of various thicknesses are compared. The AZO films were deposited on a glass substrate by FTS (Facing-Target-Sputtering) This research was conducted to find the optimal thickness for Transparent Conductive Oxide (TCO). AZO has suitable properties for TCO such as low resistivity, and high transmittance. Thin films of all thicknesses showed a transmittance of over 80% in the visible light region and electrical properties improved as thickness increased. It was confirmed that the film of 300 nm thick had the best performance due to its low resistivity, and uniform surface. This research is expected to help find optimal conditions in various fields where TCO is used, such as solar cells, displays, and sensors in the future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.837-843
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• 2009

$TiO_2$(2 wt.%)-doped ZnO(TZO) films with thickness from 100 nm to 500 nm were prepared on polyethylene naphthalate(PEN) substrate under various rf-power range from 40 W to 80 W. Their electrical and optical properties were investigated as a function of rf-power. We think that these properties were closely related with the crystallization and the film density of TZO films. It was also presumed that the vaporization of the water vapor and other adsorbed particles such as an organic solvents can affect the electrical properties of the conventional transparent conductive oxide(TCO) films. On the other hand, since the TZO film deposited on glass substrate at room temperature with rf-power of 80 W shows a very low resistivity of $7.5\times10^{-4}\;\Omega{\cdot}cm$ and a very excellent transmittance over an average 85% in the visible range, that is comparable to that of ITO films. Therefore, we expect that the TZO films can be used as transparent electrode for optoelectronic devices such as touch-panels, flat-panel displays, and thin-film solar cells.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.99.2-99.2
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• 2015

현재 투명전극(Transparent Conductive Oxide: TCO)은 평판 디스플레이, 태양전지, 터치패널, 투명 트렌지스터의 전극 등 여러 분야에서 연구되어지고 있으며, 주로 IT 산업의 핵심재료로 ITO (Indium Tin Oxide)가 사용되고 있다. ITO 박막은 주로 스퍼터 공정을 통해 제작이 되며, 전기전도도가 우수하며 높은 Optical Band Gap을 가지고 있어 투명전극으로 많이 사용되고 연구되어지고 있다. 산화물 박막을 증착할 때 산소유량에 따라 박막의 물성이 변하거나 박막의 특성이 저하되는 현상 등을 가지고 있어 공정시 산소유량이 중요한 변수로 작용하게 된다. 본 연구에서는 증착 공정 중 발생하는 플라즈마의 방출광을 가지고 산소의 대표적인 파장의 방출광을 관찰하여 방출광이 변화함에 따라 실시간으로 산소가스유량이 제어됨을 확인하였으며, 또한 산소유량제어를 통해 생성된 박막의 전기적 특성 및 광학적 특성 등 박막의 물성을 비교하였다.