• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1333-1334
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• 2005

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.319-322
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• 2004

ZnO nanostructures were formed on a Si substrate by off-axis pulsed laser deposition(PLD) system in which a substrate plane was tilted toward a plume propagation direction. Atomic force microscopy (AFM) showed islands of 20∼40 nm width. From the x-ray diffraction (XRD) pattern exhibiting only (002) ZnO peak, the islands observed in AFM image were found to well crystallized. Optical bandgap enlargement from 3.26 eV to 3.35 and 3.47 eV due to the quantum size effect of ZnO nanostructures were observed by Photoluminescence (PL) at room temperature.

• 한국재료학회지
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• 제17권3호
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• pp.125-131
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• 2007

[ $TiO_{2}-solution$ ] was aaded in $SiO_{2}-solution$ by various composition. $SiO_{2}-TiO_{2}$ thin films were obtained by the dip-coating method on the $SiO_{2}$ glass substrates, and then heat-treated at various temperature. Nano-size $TiO_{2}$ particles dispersed $SiO_{2}-TiO_{2}$ films showed absorption peak by quantum size effect at short wavelength region $350{\sim}400nm$, which made them good candidates for non-linear optical materials and photo-catalytic materials. The thickness of $SiO_{2}-TiO_{2}$ films were $300{\sim}430nm$. The contact angle of $SiO_{2}-TiO_{2}$ films for water was $5.3{\sim}47.9^{\circ}$, and therefore it is clear that $SiO_{2}-TiO_{2}$ films have super hydrophilic properties and the self-cleaning effects.

• ETRI Journal
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• 제36권1호
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• pp.89-98
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• 2014

The integration of digital circuits has a tight relation with the scaling down of silicon technology. The continuous scaling down of the feature size of CMOS devices enters the nanoscale, which results in such destructive effects as short channel effects. Consequently, efforts to replace silicon technology with efficient substitutes have been made. The carbon nanotube field-effect transistor (CNTFET) is one of the most promising replacements for this purpose because of its essential characteristics. Various digital CNTFET-based circuits, such as standard logic cells, have been designed and the results demonstrate improvements in the delay and energy consumption of these circuits. In this paper, a new CNTFET-based 5-input XOR gate based on a novel design method is proposed and simulated using the HSPICE tool based on the compact SPICE model for the CNTFET at the 32-nm technology node. The proposed method leads to improvements in performance and device count compared to the conventional CMOS-style design.

• 대한전자공학회논문지
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• 제18권6호
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• pp.30-37
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• 1981

두께가 30μm인 다결정 실리콘 p-n 접합 태양전지의 삼차원적인 반송자 분포, 양자효율 및 변환효율(AMI)을 계산하였다. 다결정 및 단결정 실리콘 태양전지의 양자효율이 비교되었다. Grain 크기가 각각 5μm, 100μm인 전지의 효율은 6%, 12%로 계산되었다.

• Nano
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• 제13권10호
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• pp.1850114.1-1850114.7
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• 2018

Here we report an optimized hot-injection method and a phase transfer strategy for the synthesis of water-soluble $CuInS_2$ QDs with desired properties. The structure and morphology studies demonstrate that the resulting QDs are $CuInS_2$ tetragonal phase with well-defined facets. It is also found that the crystal size gradually increases with the increase of reaction temperature, while the surface of QDs with pre- and post-phase transfer is functionalized with hydrophobic and hydrophilic ligands, respectively. Spectroscopy measurements reveal the size-dependent optical properties of $CuInS_2$ QDs, demonstrating the quantum confinement effect in this system.

• 한국진공학회지
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• 제10권2호
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• pp.247-251
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• 2001

실리콘산화막에 $Si^+$이온을 주입하여 열처리를 한 후 상온에서 8K까지 온도를 변화시키며 PL을 측정하였다. 상온에서 50~80K까지는 PL intensity가 전체적으로 증가하였으며 50K 이하에서는 감소하였다. PL intensity가 증가하는 동안 peaks는 blue-shift가 일어났다. PL spectrum에서 peak를 보이는 파장에서 PL의 온도의존성을 측정하였다. 첫 번째 peak가 온도변화에 가장 민감하며 크기가 작은 peak일수록 온도의 영향을 적게 받는다. PL peak의 온도의존성을 분석하였다. 상온에서 50K 범위에서 PL intensity 대 1000/T그림에서 온도역수의 3차 함수로 fitting할 수 있었다. 온도가 내려갈수록 PL intensity가 증가하는 것을 nanocrystal 보다도 O위주 결함(Si-O-O)이나 Si위주 결함(Si-Si-O)들의 quantum size effect로 설명할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.558-561
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• 2001

In this study, the ZnS nanosized thin films were grown by the solution growth technique (SGT), and their structural and optical properties were examined. X-ray diffraction patterns showed that the ZnS thin film obtained in this study had the cubic structure ($\beta$-ZnS). With decreasing growth temperature and decreasing concentration of precursor solution, the surface morphology of film was found to be improved. In particular, this is the first time that the surface morphology dependence of ZnS film grown by SGT on the ammonia concentration is reported. The energy band gaps of samples were shown to vary from 3.69 eV to 3.91 eV, demonstrating that the quantum size effect of SGT grown ZnS is remarkable. Photoluminescence (PL) peaks were observed at the positions corresponding to the lower energy than that to energy band gap, illustrating that the surface states were induced by the ultra-fineness of grains in ZnS films.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4585-4600
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• 2022

A pool scrubber is often used as a wet-type design to mitigate the consequence of a severe nuclear accident. While studies indicated higher decontamination performance of a deeper pool, utilizing a very tall pool can be problematic due to potential structural stability and water backflow issues. This study proposes, as an alternative to a single pool system, a pool scrubber system composed of serially connected multiple pools with lower heights. Since large fraction of aerosol removal takes place in the injection region, serially connected pool scrubber system is expected to enhance the overall decontamination capability of a pool scrubber system. To support the analysis of the proposed system's decontamination capability, a new computer model was developed in the study to describe the bubble size dependent effect on aerosol removal including the effect of pool residence time. The accuracy of the new model was examined against experimental data for its validation. The proposed scrubber system composed of serially connected multiple shorter pools is found to have much improved decontamination performance over the current single pool system design.

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1562-1566
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• 2006

Mesoporous silica films with three different pore sizes were prepared by using cationic surfactant, non-ionic surfactant, or triblock copolymer as structure directing agents with tetramethylorthosilicate as silica source in order to control the pore size and wall thickness. They were synthesized by an evaporation-induced self-assembly process and spin-coated on Si wafer. Mesoporous silica films with three different pore sizes of 2.9, 4.6, and 6.6 nm and wall thickness ranging from $\sim$1 to $\sim$3 nm were prepared by using three different surfactants. These materials were optically transparent mesoporous silica films and crack free when thickness was less than 1 m m. The photoluminescence spectra found in the visible range were peaked at higher energy for smaller pore and thinner wall sized materials, consistent with the quantum confinement effect within the nano-sized walls of the silica pores.