• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.789-794
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• 2008

Zinc oxide (ZnO) has been widely studied for its practical applications such as transparent conduction electrodes for flat panel displays and solar cells. Especially, ZnO films show good chemical stability against hydrogen plasma, absence of toxicity, abundance in nature, and then suitable for photovoltaic applications. However, the fabrication process of thin film solar cells require a high substrate temperature and/or post heat treatment. Therefore, the layers have to withstand high temperatures, requiring an excellent stability without degrading their electronic and optical properties. In this paper, we investigated the stability of zinc oxide (ZnO) films doped with aluminum and hydrogen. Doped ZnO films were prepared by r.f. magnetron sputter and followed by heat treatment at different temperatures and for various times.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1367-1368
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• 2007

We prepared Zinc Oxide thin films introducing Ag layer on glass substrates at room temperature by using facing targets sputtering (FTS) method. In order to obtain good electrical properties, Ag layer was introduced. Ag with various thickness of thin films were used as intermediate layers. The electrical, optical and crystallographic properties of thin films were investigated by Four-Point probe, UV/VIS spectrometer and XRD. From the results, we could confirm that the thickness of Ag layer changes the electrical and optical performances of the multilayers.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.146-146
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• 2016

Zinc Oxide (ZnO) was known as a promising material for surface acoustic wave devices, gas sensors, optical devices and solar cells due to piezoelectric material, large band gap of 3.37 eV and large exciton binding energy of 60 meV at room temperature. In particular, the alignment of ZnO nanostructures into ordered nanoarrays can bring about improved sensitivity of devices due to widen the surface area to catch a lot of gas particle. Oxygen plasma treatment is used to specify the nucleation site of round patterned ZnO nanorods growth. Therefore ZnO nanorods were grown on a quartz substrate with patterned polystyrene monolayer by hydrothermal method after oxygen plasma treatment. And then, we carried out nanostructures by adjusting the diameter of the arranged ZnO nanorods according to polystyrene spheres of various sizes. The obtained ZnO nanostructures was characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM).

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.501-507
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• 2010

Three hundred chicks were randomly assigned among four treatments to evaluate the effect of an organic selenium supplement at various levels of dietary protein. Two levels of supplemental selenium (0 and 0.3 mg/kg) from zinc-L-selenomethionine were tested at two levels of dietary protein (normal and reduced) in a completely randomized design with $2{\times}2$ factorial layout. The experiment lasted up to 49 d of age during which all birds were exposed to $31{\pm}1^{\circ}C$. The effects of selenium or its interaction with CP on growth performance and carcass characteristics were not significant. However, feeding the reduced-CP diet decreased weight gain in the starting period and increased liver and abdominal fat weights relative to body weight. Ferric reducing ability of plasma (FRAP) was not significantly affected by dietary CP and Se or their interaction though FRAP values were numerically higher in the Se-supplemented group. Dietary CP content did not affect the activity of plasma glutathione peroxidase (GSHPx), though Se significantly elevated plasma GSHPx activity. The interaction of CP and Se was not significant for FRAP and plasma GSHPx activity.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1564-1567
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• 2005

Zinc oxide thin films were grown at the t emperature of $100^{\circ}C$ and $150^{\circ}C$ by means of plasma enhanced atomic layer deposition (PEALD) and conventional atomic layer deposition for applying to the transparent thin film transistor (TTFT). The growth rate of $1.9{\AA}/cycle$ with oxygen plasma is similar to that of film grown with water. While the sheet resistivity of ZnO grown with water is 1233 ohm/sq, that of film grown with oxygen plasma was too high to measure with 4 point probe and hall measurement system. The resistivity of the films grown with oxygen plasma estimated to be $10^6$ times larger than that of the films grown with water. The difference of electrical property between two films was caused by the O/Zn atomic ratio. We fabricated ZnO-TFT by means of ALD for the first time and the ZnO channel fabricated with water showed saturation mobility of $0.398cm^2/V{\cdot}s$ with bottom gate configuration.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1352-1353
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• 2008

In this study, aluminium - doped zinc oxide (ZnO:Al) transparent conducting film was deposited on PET(polyethylen terephthalate) substrate by r.f. magnetron sputtering method. PET substrate was surface-treated in an atmospheric pressure DBD(dielectric barrier discharge) plasma to increase deposition rate and to improve electrical propesties. Morphological changes by DBD plasma were obsered using contact angle measurement. The contact angle of water on PET was reduced from 62$^{\circ}$ to 42$^{\circ}$ by DBD plasma surface treatment. The plasma treatment also increased deposition rate and electrical propesties. The electrical resistivity as low as $4.97{\times}10^{-3}[{\Omega}-cm]$ and the deposition rate of 234[${\AA}$-m/min] were obtained in ZnO:Al film with surface treatment time of 5min, and 20min., respectively.

• Nutritional Sciences
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• v.6 no.4
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• pp.232-238
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• 2003

Cardiovascular disease (CVD) is one of the most common causes of death in elderly Koreans, and HDL-cholesterol is known to have a pivotal role in protecting against CVD. This study was undertaken to study the relationships between plasma HDL-cholesterol levels and dietary, anthropometric, and biochemical factors in elderly Koreans. The 102 subjects, who were over 60 years old, were classified into two groups based on their plasma HDL-cholesterol levels: a risk group with plasma HDL-cholesterol < 40mg/dl in men or HDL-cholesterol < 50mg/d1 in women, and a control group with higher HDL-cholesterol levels. The subjects' mean intakes of energy, calcium, zinc, vitamin A, vitamin $B_2$, vitamin E, and folate did not meet the Korean RDA for elderly people. Vitamin $B_2$ and folate intakes were significantly lower (p<0.l) in the risk group compared to the control group. The consumption of seaweed was significantly lower (p<0.05), and fish intake was 33% lower, in the risk group compared to the control group. Subjects in the risk group showed a higher BMI, waist/hip ratio, triceps skinfold thickness, and % body fat, compared to control subjects. Plasma triglyceride levels and values of the atherogenic index were significantly higher (p<0.00l) in risk group subjects. Significant negative correlations between HDL-cholesterol level and plasma triglyceride level (r= 0.37), and values of the atherogenic index (r=-0.74), were found. In summary, subjects with low levels of HDL-cholesterol were found to have relatively low intakes of vitamin B$_2$, folate, and seaweed, and higher levels of the CVD risk factors: body fat, plasma TG, and AI. These results suggest that plasma HDL-cholesterol levels can be modified by dietary, anthropometric, and hematological means.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.35-40
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• 2010

We have investigated the effects of hydrogen injection via in-situ gas addition ($O_2$, $H_2$, or $O_2$ + $H_2$ gas) and plasma post-treatment (Ar or Ar + H plasma) on material properties of ZnO that is considered to be as a channel layer in transparent thin film transistors. The variations in the electrical resistivity, optical transmittance and bandgap energy, and crystal quality of ZnO thin films were characterized in terms of the methods and conditions used in hydrogen injection. The resistivity was significantly decreased by injection of hydrogen; approximately $10^6\;{\Omega}cm$ for as-grown, $1.2\;{\times}\;10^2\;{\Omega}cm$ for in-situ with $O_2/H_2\;=\;2/3$ addition, and $0.1\;{\Omega}cm$ after Ar + H plasma treatment of 90 min. The average transmittance of ZnO films measured at a wavelength of 400-700 nm was gradually increased by increasing the post-treatment time in Ar + H plasma. The optical bandgap energy of ZnO films was almost monotonically increased by decreasing the $O_2/H_2$ ratio in in-situ gas addition or by increasing the post-treatment time in Ar + H plasma, while the post-treatment using Ar plasma hardly affected the bandgap energy. The role of hydrogen in ZnO was discussed by considering the creation and annihilation of oxygen vacancies as well as the formation of shallow donors by hydrogen.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.24-28
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• 2007

The etching of zinc oxide (ZnO) thin films has been studied using a high density plasma in a $Cl_2/Ar$ gas. The etch characteristics of ZnO thin films were systematically investigated on varying $Cl_2$ concentration, coil rf power, dc-bias voltage, and gas pressure. With increasing $Cl_2$ concentration, the etch rate of ZnO thin film increased, the redeposition around the etched patterns decreased but the sidewall slope of the etched patterns slanted. As the coil rf power and dc-bias voltage increased, the etch rates of ZnO thin films increased and etch profiles of ZnO thin films were improved. With increasing gas pressure, the etch rate of ZnO thin films slightly increased but little change in etch profile was observed. Based on these results, the optimal etching conditions of ZnO thin film were selected. Finally, the etching of ZnO thin films with a high degree of anisotropy of approximately $75^{\circ}{\sim}80^{\circ}$ without the redepositions and residues was successfully achieved at the etching conditions of 20% $Cl_2$ concentration, coil rf power of 1000 W, dc-bias voltage of 400 V, and gas pressure of 5 mTorr.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.296-301
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• 2009

An inductively coupled plasma assisted atomic layer deposition(ICP-ALD) system has been constructed for the deposition of ZnO thin films, and various experiments of ZnO thin films on p-type Si(100) substrates have been carried out to find the self-limiting reaction conditions for the ICP-ALD system under non-plasma circumstances. Diethyl zinc[$Zn(C_2H_5)_2$, DEZn] was used as the zinc precursor, $H_2O$ as the oxidant, and Ar as the carrier and purge gas. At the substrate temperature of $150^{\circ}C$, atomic layer deposition conditions based on self-limiting surface reaction were successfully obtained by series of experiments through the variation of exposure times for DEZn, $H_2O$, and Ar. ZnO deposition was repeated at different substrate temperatures of $90{\sim}210^{\circ}C$. As a result, the thermal process window(ALD window) for ZnO thin films was observed to be $110{\sim}190^{\circ}C$ and the average growth rate was measured to be constant of 0.29 nm/cycle. Properties of the film's microstructure and composition(Zn, O, etc.) were also studied. As the substrate temperature increases, the crystallinity was improved and ZnO(002) peak became dominant. The films deposited at all temperatures were high purity, and the films deposited at high temperatures had the composition ratio between Zn and O closer to one of a stable hexagonal wurtzite structure.