• 한국표면공학회지
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• 제38권5호
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• pp.179-182
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• 2005

Indium Tin Oxide (ITO) thin films were deposited from various target densities ($98.7\%\~99.6\%$) using RF magnetron sputtering. Effect of the sputtering target densities on the structural, electrical and optical properties of deposited ITO thin films was investigated. The preferable (400) crystalline orientation peak was observed on the films deposited from > $99.0\%$ target density. Higher target density produced films with higher roughness but lower resistivity. All of the deposited films showed optical transmittance more than $85\%$ in the visible wavelength region. It is necessary to use the highest target density for sputtering deposition of ITO thin films.

• Applied Science and Convergence Technology
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• 제24권6호
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• pp.242-244
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• 2015

ZnO:Ga thin films were deposited by RF magnetron sputtering technique from ZnO (3 wt.% $Ga_2O_3$) target onto glass substrates under various RF power. The influence of RF power on the structural, electrical, and optical properties of ZnO:Ga thin films was investigated by X-ray diffraction, atomic force microscopy, Hall method and optical transmission spectroscopy. As the RF power increases from 50 to 110W, the crystallinity is deteriorated, the root main square surface roughness is decreased and the sheet resistance is increased. The increase of sheet resistance is caused by decreasing carrier concentration due to interstitial Ga ion. All films are transparent up to 80% in the visible wavelength range and the adsorption edge is a red-shift with increasing RF power.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.68.2-68.2
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• 2012

We present a scheme for monolithically integrating aligned arrays of single walled carbon nanotubes (SWNTs) with sheets of graphene, for use in electronic devices. Here, the graphene and arrays of SWNTs are formed separately, using chemical vapor deposition techniques onto different, optimized growth substrates. Techniques of transfer printing provide a route to integration, yielding two terminal devices and transistors in which patterned structures of graphene form the electrodes and the SWNTs arrays serve as the semiconductor. Electrical testing and analysis reveal the properties of optically transparent transistors that use this design, thereby giving insights into the nature of contacts between graphene and SWNTs.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.64.1-64.1
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• 2012

Next generation displays such as high performance LCD, AMOLED, flexible display and transparent display require specific TFT back-planes. For high performance TFT back-planes, low temperature poly silicon (LTPS), and metal-oxide semiconductors are studied. Flexible TFT backplanes require low temperature processible organic semiconductors. Not only development of active semiconducting materials but also design and synthesis of semiconductor corresponding gate dielectric materials are important issues in those display back-planes. In this study, we investigate the high heat resistant polymeric gate dielectric materials for organic TFT and inorganic TFT with good insulating properties and processing chemical resistance. We also controlled and optimized surface energy and morphology of gate dielectric layers for direct printing process with solution processible organic and inorganic semiconductors.

• Journal of the Optical Society of Korea
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• 제2권1호
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• pp.13-21
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• 1998

Based on the escape cone concepts, high-brightness light-emitting diodes (LEDs) have been analyzed. In AlGaAs or InGaAlP LEDs, photon absorption in the ohmic region under the electrode is known to be significant. Thus, ins general, a thick window layer (WL) and a transparent substrate (TS) would minimize photon shielding by the electrodes and considerably improve photon output coupling efficiency. However, the schemes do not seem to be necessary in InGaN system. Photon absorption in ohmic contact to a wide bandgap semiconductor such as GaN may be negligible and, as a result, the significant photon shielding by the electrodes will not degrade the photon output coupling efficiency so much. The photon output coupling efficiency estimated in InGaN LEDs is about 2.5 - 2.8 times that of the conventional high-brightness LED structures based on both WL and TS schemes. As a result, the extenal quantum efficiency in InGaN LEDs is as high as 9% despite the presumably very low internal quantum efficiency.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권1호
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• pp.51-54
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• 2009

Transparent Cuprous oxide film was deposited by rapid thermal oxidation (RTO) of Cu at $500^{\circ}C$/45s condition on textured single-crystal n-Si substrate to form $Cu_2O$/n-Si heterojunction photodiode. The Hall effect measurements for the $Cu_2O$ films showed a p-type conductivity. The photovoltaic and electrical properties of the junction at room temperature were investigated without any post-deposition annealing. I-V characteristics revealed that the junction has good rectifying properties. The C-V data showed abrupt junction and a built-in potential of 1 V. The photodiode showed good stability and high responsivity in the visible at three regions; 525 nm, 625-700 nm, and 750nm denoted as regions A, B, and C, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.307-308
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• 2008

Zinc oxide is a direct band gap wurtzite-type semiconductor with band gap energy of 3.37eV at room temperature. the n-type doped ZnO oxides, B doped ZnO (BZO) is widely studied in TCOs materials as it shows good electrical, optical, and luminescent properties. we focused on the fabrication of B doped ZnO films with glass substrate using the LSMCD at low temperature. And Novel boron-doped ZnO thin films were deposited and characterized from the structural, optical, electrical point of view. The structure, morphology, and optical properties of the films were studied as a function of by employing the XRD, SEM, Hall system and micro Raman system.

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 2001년도 제32차 추계학술대회
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• pp.18-22
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• 2001

A technique to characterize specific site of materials using a combination of a dedicated focused ion beam system(FIB), and Intermediate-voltage scanning transmission electron microscope(STEM) or transmission electron microscope(TEM) equipped with a scanning electron microscope(SEM) unit has been developed. The FIB system is used for preparation of electron transparent thin samples, while STEM or TEM is used for localization of a specific site to be milled in the FIB system. An FIB-STEM(TEM) compatible sample holder has been developed to facilitate thin sample preparation with high positional accuracy Positional accuracy of $0.1{\mu}m$ or better can be achieved by the technique. In addition, an FIB micro-sampling technique has been developed to extract a small sample directly from a bulk sample in a FIB system These newly developed techniques were applied for the analysis of specific failure in Si devices and also for characterization of a specific precipitate In a metal sample.

• 한국정밀공학회지
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• 제12권12호
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• pp.91-99
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• 1995

An effort has been made to more accurately analyze the flow in the chip cavity, particularly to model the flow through the openings in the leadframe and correctly treat the thermal boundary condition at the leadframe. The theoretical analysis of the flow has been done by using the Hele- Shaw approximation in each cavity separated by a leadframe. The cross-flow through the openings in the leadframe has been incorporated into the Hele-Shaw formulation as a mass source term. The temperature of the leadframe has been calculated based on energy balance in the leadframe. The flow behavior in the leadframe has been verified experimentally. In the experiment, a transparent mold and clear fluid have been used for flow visualization. Comparisons were made between the calculation and experimental results which showed a good agreement.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.334-334
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• 2012

Transparent oxide semiconductors have recently attracted much attention as channel layer materials due to advantageous electrical and optical characteristics such as high mobility, high stability, and good transparency. In addition, transparent oxide semiconductor can be fabricated at low temperature with a low production cost and it permits highly uniform devices such as large area displays. A variety of thin film transistors (TFTs) have been studied including ZnO, InZnO, and InGaZnO as the channel layer. Recently, there are many studies for substitution of Ga in InGaZnO TFTs due to their problem, such as stability of devices. In this work, new quaternary compound materials, tantalum-indium-tin oxide (TaInSnO) thin films were fabricated by using co-sputtering and used for the active channel layer in thin film transistors (TFTs). We deposited TaInSnO films in a mixed gas (O2+Ar) atmosphere by co-sputtering from Ta and ITO targets, respectively. The electric characteristics of TaInSnO TFTs and thin films were investigated according to the RF power applied to the $Ta_2O_5$ target. The addition of Ta elements could suppress the formation of oxygen vacancies because of the stronger oxidation tendency of Ta relative to that of In or Sn. Therefore the free carrier density decreased with increasing RF power of $Ta_2O_5$ in TaInSnO thin film. The optimized characteristics of TaInSnO TFT showed an on/off current ratio of $1.4{\times}108$, a threshold voltage of 2.91 V, a field-effect mobility of 2.37 cm2/Vs, and a subthreshold swing of 0.48 V/dec.