• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.19-22
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• 2007

Optic tweezer is powerful tool to investigate biologic cells. Of eukaryotic cells, it was poorly documented regarding to optic trapping to manipulate yeasts. In preliminary experiment to explore yeast biology, interferometric optical tweezers was exploited to trap and manipulate budding yeasts. Successfully, several budding yeasts are trapped simultaneously. We found that the budding direction of the daughter cell was almost outward and the daughter cell surrounded by other yeasts grows slowly or fail to grow. Thus it was assumed that neighboring cells around budding yeast may be critical in budding and the growth of daughter cells. This is first report pertaining to the pattern of yeast budding under the optical trap when multiple yeasts were trapped.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.260-262
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• 2005

Thickness optimization of heavily doped p-type seeding layer was studied to improve performance of thin film silicon solar cell. We used liquid phase epitaxy (LPE) to grow active layer of $25{\mu}m$ thickness on $p^+$ seeding layer. The cells with $p^+$ seeding layer of $10{\mu}m\;to\;50{\mu}m$ thickness were fabricated. The highest efficiency of a cell is 12.95%, with $V_{oc}=633mV,\;J_{sc}=26.5mA/cm^2$, FF = 77.15%. The $p^+$ seeding layer of the cell is $20{\mu}m$ thick. As thicker seeding layer than $20{\mu}m$, the performance of the cell was degraded. The results demonstrate that the part of the recombination current is due to the heavily doped seeding layer. Thickness of heavily doped p-type seeding layer was optimized to $20{\mu}m$. The performance of solar cell is expected to improve with the incorporation of light trapping as texturing and AR coating.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.168-171
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• 2005

Thickness optimization of heavily doped p-type seeding layer was studied to improve performance of thin film silicon solar cell. We used liquid phase epitaxy (LPE) to grow active layer of $25{\MU}m$ thickness on p+ seeding layer. The cells with p+ seeding layer of $10{\mu}m\;to\;50{\mu}m$ thickness were fabricated. The highest efficiency of a cell is $12.95\%$, with Voc=633mV, $Jsc=26.5mA/cm^2,\;FF=77.15\%$. The $P^+$ seeding layer of the cell is $20{\mu}m$, thick. As thicker seeding layer than $20{\mu}m$, the performance of the cell was degraded. The results demonstrate that the part of the recombination current is due to the heavily doped seeding layer. Thickness of heavily doped p-type seeding layer was optimized to $20{\mu}m$. The performance of solar cell is expected to improve with the incorporation of light trapping as texturing and AR coating.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.98-103
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• 2016

The surface morphology of the front transparent conductive oxide (TCO) films plays a vital role in amorphous silicon thin film solar cells (a-Si TFSCs) due to their high transparency, conductivity and excellent light scattering properties. Recently, plasma textured glass surface morphologies received much attention for light trapping in a-Si TFSCs. We report various plasma textured glass surface morphologies for the high efficiency of a-Si TFSCs. Plasma textured glass surface morphologies showed high rms roughness, haze ratio with micro- and nano size surface features and are proposed for future high efficiency of a-Si TFSCs.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1538-1544
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• 2004

Fragmentations and proton transfer reactions of mono-, di-, and triethanolamines were studied using FTMS. It was found that the most abundant fragment ion was $[M-CH_2OH]^+$. The $[M-CH_2OH-H_2O]^+$ was observed in the mass spectra of diethanolamine and triethanolamine. By increasing the ion trapping time in the ICR cell, the $[M+H]^+$ and $[M+H-H_2O]^+$ ions were notably increased for all the samples while the $[M+H-2H_2O]^+$ was observed in the mass spectra of diethanolamine and triethanolamine. The proton transfer reactions between the fragment ions and neutral molecules occurred predominantly by increasing the ion trapping time. The rate constants for the proton transfer reactions were calculated from experimental results. The proton transfer reaction of $CHO^+$ was the fastest one, which is consistent with the heats of reaction. The rate constants for proton transfer reactions of triethanolamine were much slower than those of ethanolamine and diethanolamine because of the steric hindered structure of triethanolamine. The plausible structures of observed ions and heats of reaction for proton transfer were calculated with AM1 semiempirical method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.3
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• pp.337-344
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• 2024

This work focuses on improving the light-harvesting efficiency of thin-film silicon solar cells through innovative multi-architecture surface modifications. To create a regular optical structure, a lithographic process was performed to form it on a glass substrate through various etching processes, from Etch-1 to Etch-3. AZO was deposited on top of the structures and re-etched to create a multi-architectural surface. These surface-modified structures improved the light absorption and overall performance of the solar cell through changes in optical and physical properties, which we will analyze. In addition, we investigated the effect of post-cleaning on the etched glass structures through EDX analysis to understand the mechanism of the etching action. The results of this study are expected to provide important guidelines for the design and fabrication of solar cells and other photovoltaic devices.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.1-6
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• 2006

We investigated the characteristics of the nonlinear magneto-optic effect (NMOE) depend on the transitions, the laser intensity and the temperature of the vapor cell, in the $D_1$ transition of $^{87}Rb$ atoms by using the Rb vapor cell contained with buffer gas of Ne 6.7 kPa. The size and the width of NMOE signal were increased according to the light intensity and temperature in the transition of F=2$\to$F'=2. However, In the case of using the F=2$\to$F'=1 transition, the size of the signal could be increased according to the light intensity without additional broadening of the width. We confirmed that the sensitivity of detecting small magnetic flux improved in this transition, and explained these effects by the different of the CPT configuration between Zeeman sublevels. At the optimal condition in experiment, the sensitivity of this system was evaluated less then $70pT/\sqrt{Hz}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.419-419
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• 2016

High efficiency silicon solar cell requires the textured front surface to reduce reflectance and to improve the light trapping. In case of mono-crystalline silicon solar cell, wet etching with alkaline solution is widespread. However, the alkali texturing methods are ineffective in case of multi-crystalline silicon wafer due to grain boundary of random crystallographic orientation. The acid texturing method is generally used in multi-crystalline silicon wafer to reduce the surface reflectance. However the acid textured solar cell gives low short-circuit current due to high reflectivity while it improves the open-circuit voltage. To reduce the reflectivity of multi-crystalline silicon wafer, double texturing method with combination of acid and reactive ion etching is an attractive technical solution. In this paper, we have studied to optimize RIE experimental condition with change of RF power (100W, 150W, 200W, 250W, 300W). During experiment, the gas ratio of SF6 and O2 was fixed as 30:10.

• Current Optics and Photonics
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• v.7 no.2
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• pp.207-212
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• 2023

In this paper, we introduce our system for manufacturing a Rb vapor cell and describe its fabrication process in a sequence of removing impurities, cold trapping, and sealing off. Saturated absorption spectroscopy was performed to verify the quality of our cell by comparing it to that of a commercial one. By using the lab-fabricated Rb vapor cell, we observed electromagnetically induced transparency in a ladder-type system corresponding to the 5S_1/2-5P_3/2-28D_5/2 transition of the ⁸⁵Rb atom. A highly excited Rydberg atomic system was prepared using two counter-propagating external cavity diode lasers with wavelengths of 780 nm and 480 nm. We also observed the Autler-Townes splitting signal while a radio-frequency source around 100 GHz incidents into the Rydberg atomic medium.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.56-56
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• 2009

In this study, we fabricated the engineered $SiO_2/Si_3N_4/SiO_2$(ONO) tunnel barrier with high-k $HfO_2$ trapping layer for application high performance flash MLC(Multi Level Cell). As a result, memory device show low operation voltage and stable memory characteristics with large memory window. Therefore, the engineered tunnel barrier with ONO stacks were useful structure would be effective method for high-integrated MLC memory applications.