• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.388-388
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• 2013

현대 사회에서 고집적 및 고성능의 전자소자의 필요성은 지속적으로 요구되고 있으며, 투명하거나 플렉서블한 특성의 필요성에 따라 이에 대한 기술개발이 이루어지고 있다. 특히, 이러한 특성을 만족하면서 대면적화 및 저온 공정의 특성을 지니는 유기물 반도체가 주목받고 있고, 이를 이용하여 OLED (Organic Light Emitting Diode), OTFT (Organic Thin Film Transistor)와 같은 다양한 유기물 반도체 소자가 개발되고 있다. 대표적인 예로는이 있다. 유기물 반도체 소자의 특성을 이용한 메모리 소자 또한 연구 및 개발이 지속되고 있으며, 유연성과 낮은 공정가격 등의 특성을 가지는 나노 입자들이 기존 Floating Gate의 대체물로 각광받고 있다. 본 논문에서는 MIS (Metal/Insulator/Semiconductor) 구조를 제작하고, Insulator 내부에Core/Shell 구조를 가지는 CdSe/ZnS 나노 입자를 부착하여 메모리 소자의 특성 확인 및 단위 면적당 개수에 따른 특성 변화를 확인하고자 하였다. 합성된 PVP (Poly 4-Vinyl Phenol)를 Insulator 층으로 사용하였으며 단위 면적당 나노 입자의 개수를 조절하여 제작된 MIS 소자를 Capacitance versus Voltage (C-V) 측정을 통하여 변화특성을 확인하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.118-118
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• 2011

The Nano-Floating Gate Memory(NFGM) devices with ZnO:Cu thin film embedded in Al2O3 and AlOx-SAOL were fabricated and the electrical characteristics were evaluated. To further improve the scaling and to increase the program/erase speed, the high-k dielectric with a large barrier height such as Al2O3 can also act alternatively as a blocking layer for high-speed flash memory device application. The Al2O3 layer and AlOx-SAOL were deposited by MLD system and ZnO:Cu films were deposited by ALD system. The tunneling layer which is consisted of AlOx-SAOL were sequentially deposited at $100^{\circ}C$. The floating gate is consisted of ZnO films, which are doped with copper. The floating gate of ZnO:Cu films was used for charge trap. The same as tunneling layer, floating gate were sequentially deposited at $100^{\circ}C$. By using ALD process, we could control the proportion of Cu doping in charge trap layer and observe the memory characteristic of Cu doping ratio. Also, we could control and observe the memory property which is followed by tunneling layer thickness. The thickness of ZnO:Cu films was measured by Transmission Electron Microscopy. XPS analysis was performed to determine the composition of the ZnO:Cu film deposited by ALD process. A significant threshold voltage shift of fabricated floating gate memory devices was obtained due to the charging effects of ZnO:Cu films and the memory windows was about 13V. The feasibility of ZnO:Cu films deposited between Al2O3 and AlOx-SAOL for NFGM device application was also showed. We applied our ZnO:Cu memory to thin film transistor and evaluate the electrical property. The structure of our memory thin film transistor is consisted of all organic-inorganic hybrid structure. Then, we expect that our film could be applied to high-performance flexible device.----못찾겠음......

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.799-803
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• 2018

We demonstrated memory thin-film transistors (MTFTs) with organic ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) and an amorphous oxide semiconducting indium gallium zinc oxide channel on the elastomeric substrate. The dielectric constant for the P(VDF-TrFE) thin film prepared on the elastomeric substrate was calculated to be 10 at a high frequency of 1 MHz. The voltage-dependent capacitance variations showed typical butterfly-shaped hysteresis behaviors owing to the polarization reversal in the film. The carrier mobility and memory on/off ratio of the MTFTs showed $15cm^2V^{-1}s^{-1}$ and $10^6$, respectively. This result indicates that the P(VDF-TrFE) film prepared on the elastomeric substrate exhibits ferroelectric natures. The fabricated MTFTs exhibited sufficiently encouraging device characteristics even on the elastomeric substrate to realize mechanically stretchable nonvolatile memory devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.882-885
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• 2004

Organic molecules have many properties that make them attractive for electronic applications. We have been examining the progress of memory cell by using molecular-scale switch to give an example of the application using both nanoscale components and Si-technology. In this study, molecular electronic devices were fabricated with amion style derivatives as redox-active component to compare to the devices using Zn-Porphyrin derivatives. This molecule is amphiphilic to allow monolayer formation by the Langmuir-Blodgett (LB) method, and then this LB monolayer is inserted between two metal electrodes. According to current-voltage (I-V) characteristics, it was found that the devices show remarkable hysteresis behavior and can be used as memory devices at ambient conditions, when aluminum oxide layer was existed on bottom electrode. Diode-like characteristics were measured only, when Pt layer was existed as bottom electrode. It was also found that this metal layer interacts with the organic molecules and acts as a protecting layer, when thin Ti layer was inserted between the organic molecular layer and the top Al electrode. These electrical properties of the devices may be applicable to active components for the memory and/or logic gates in the future.

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.11a
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• pp.14.1-14.1
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• 2006

• Proceedings of the Materials Research Society of Korea Conference
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• 2006.05a
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• pp.21.1-21.1
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• 2006

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.7
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• pp.615-619
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• 2008

A molecular memory device which has a structure of Al/$Al_2O_3$/ASA-15 LB monolayer/Ti/Al device, was fabricated. To study a charge transfer mechanism of molecular memory devices, current density-voltage (J-V) characteristics were measured at an increasing temperature range from 10 K to 300 K with an interval of 30 K. Strong temperature-dependent electrical property and tunneling through organic monolayer at low bias (below 0.5 V) were appeared. These experimental data were fitted by using a theoretical formula such as the Simmons model. In comparison between the theoretical and the experimental results, it was verified that the fitting results using the Simmons model about direct tunneling was fairly fitted below 0.5 V at both 300 K and 10 K. Hopping conduction was also dominant at all voltage range above 200 K due to charges trapped by defects located within the dielectric stack, including the $Al_2O_3$, organic monolayer and Ti interfaces.

• ETRI Journal
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• v.35 no.4
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• pp.734-737
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• 2013

Nonvolatile ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) memory based on an organic thin-film transistor with inkjet-printed dodecyl-substituted thienylenevinylene-thiophene copolymer (PC12TV12T) as the active layer is developed. The memory window is 4.5 V with a gate voltage sweep of -12.5 V to 12.5 V. The field effect mobility, on/off ratio, and gate leakage current are 0.1 $cm^2/Vs$, $10^5$, and $10^{-10}$ A, respectively. Although the retention behaviors should be improved and optimized, the obtained characteristics are very promising for future flexible electronics.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.195.2-195.2
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• 2013

플라즈마 중합 증착기술을 이용하여 ppMMA (plasma polymerized methyl methacrylate) 및 ppS (plasma polymerized styrene) 박막을 제작하고, ppMMA를 게이트 절연층, polymer electret인 ppS를 메모리층으로 한 전계효과트랜지스터 기반 유기 메모리 소자를 제작하였다. 메모리층인 ppS의 두께를 각각 30, 60, 90 nm로 달리한 유기 메모리 소자가 C-V 및 I-V 특성에서 나타내는 히스테리시스 현상을 분석하여 메모리 특성을 평가했으며, 메모리층의 두께 변화에 따른 유기 메모리 소자의 성능을 비교분석하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.281-284
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• 2004

Photo-induced memory effect of an organic light-emitting diode(OLED) composed of a hydrazone-derivative(DBAH) dispersed in bis-phenol-A type polycarbonate polymer(PCA) in the presence of thio-Michler's ketone, was investigated by the measuring of the current density and luminance at the various conditions. After the light exposure, the current of the OLED was decreased approximately one order, and the luminance of the OLED also decresed. This memory effct was erasable by heating the OLED to the temperature higher than the glass transition temperature(Tg). As shown in this result, we found the memory effect was erased by heating and returned to its original state in the hole injecting layer(HIL) of the OLED. A series of these phenomena was suggested the possibility of the application to the imaging plate.