• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1628-1630
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• 2002

In this paper, we measured 3-dimensional temporal behavior of the light emitted from discharge cell of plasma display panel(PDP) as a function of the pressure using the scanned point detecting system. The detected light signal through the PM tube is sent on the oscilloscope and oscilloscope which is connected to PC with GPIB. The whole system is controlled by a PC. From the temporal behavior results, we could analyze the discharge behavior of panel with Ne-Xe(4%) mixing gas and 300torr, 400torr, 500torr pressure. The top view of panel shows that the discharge moves from inner edge of cathode electrode to outer cathode electrode forming arc type. At the 300torr, initial emission time is very fast. The side view of panel shows that the light is detected up to $150{\mu}m$ height of barrier rib. In the panel of 300torr, emission distribution is wider than the others.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.277-278
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• 2005

Admittance Spectroscopic analysis was applied to study the effect of LiF buffer layer and to model the equivalent circuit for poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV)-based polymer light emitting diodes (PLEDs) with the LiF cathode buffer layer. The single layer device with ITO/MEH-PPV/Al structure can be modeled as a simple parallel combination of resistor and capacitor. Insertion of a LiF layer at the Al/MEH-PPV interface shifts the highest occupied molecular orbital level and the vacuum level of the MEH-PPV layer as a result the barrier height for electron injection at the Al/MEH-PPV interface is reduced. The admittance spectroscopy measurement of the devices with the LiF cathode buffer layer shows reduction in contact resistance ($R_c$), parallel resistance ($R_p$) and increment in parallel capacitance ($C_p$).

• Journal of Community Nutrition
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• v.2 no.1
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• pp.36-49
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• 2000

Evaluation of nutritional status is an essential element in providing appropriate intervention strategies to achieve the highest level of health, Nutritional assessment of the older population is complicated by many factors which do not significantly affect the nutritional status in young adults, therefore, it should be considered in two ways; community-dwelling elders group and hospitalized or institutionalized elderly group. To sort out the individuals with nutritional problems in a community efficiently, nutrition screening tools must be simple, relatively inexpensive, and applicable to a large number of subjects. Combination of tools and indicators such as 24-hour food recall, body weight and height, and questionnaires on eating practices, and the presence of chronic diseases is practically applicable as basic tools of nutritional screening of older age group. However, the lack of validated screening techniques remains a barrier in improving nutrition. Validation is only limited to energy, BMI, protein intake of the older populations living in western countries. Further refinement of nutritional assessment tools is demanded to figure out whether those are practically applicable to community-living older adults in Asian Society. A careful and systematic evaluation of nutritional assessment tools should be carried out prior to implementation of stepwise nutrition service to the heterogeneous older population. For an in-depth nutritional assessment at the individual level, we need to extend research efforts to clarify the requirements of nutrients due to aging and diseases. More cost-effective method that will allow rapid analysis of survey results are needed so that information can be readily available to policymakers.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.114-114
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• 2012

Metal-oxide-semiconductor field-effect transistors (MOSFETs)의 critical dimension (CD)가 sub 45 nm로 줄어듬에 따라 기존에 gate dielectric으로 사용하고 있는 SiO2에서 발생되는 high gate leakage current 때문에 새로운 high dielectric constant (k) 물질들이 연구되기 시작하였다. 여러 가지 high-k 물질 중에서, aluminum-oxide (Al2O3)는 높은 dielectric constant (~10)와 전자 터널링 barrier height (~2eV) 등을 가지기 때문에 많은 연구가 되고 있다. 그러나 Al2O3를 anisotropic한 patterning을 하기 위해 주로 사용되고 있는 halogen-based 플라즈마 식각 과정에서 나타나는 Al2O3와 하부 layer간의 낮은 식각 selectivity 뿐만 아니라 표면에 발생되는 defect, stoichiometry modification, roughness 변화 등의 많은 문제점들로 인하여 device performance가 감소하기 때문에 이를 해결하기 위한 많은 연구들이 진행중이다. 따라서 본 연구에서는 실리콘 기판위의 atomic layer deposition (ALD)로 증착된 Al2O3를 BCl3/Ar 중성빔을 이용하여 원자층 식각한 후 식각 특성을 분석해 보았다. Al2O3 표면을 BCl3로 absorption시킨 후 Ar 중성빔으로 desorption 시키는 과정에서 volatile한 aluminum-chlorides와 boron oxychloride가 형성되어 layer by layer로 제거됨을 관찰 할 수 있었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1037-1043
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• 2006

We report the enhancement of hole injection using ozone-treated Ag nanodots dispersed on indium tin oxide anode in $Ir(ppy)_3-doped$ phosphorescent OLED. Phosphorescent OLED fabricated on Ag nanodots dispersed ITO anode showed a lower turn on voltage and higher luminescence than those of OLEDS prepared commercial ITO anode. Synchrotron x-ray scattering examination results showed that the Ag nanodots dispersed on ITO anode is amorphous structure due to low deposition temperature. It was thought that decrease of the energy barrier height as Ag nanodots changed to $AgO_x$ nanodots by surface treatment using ozone for 10 min led to enhancement of hole injection in phosphorescent OLED. Futhermore, efficient hole injection can be explained by increase of contact region between anode material and organic material through introduction of $Ag_2O$ nanodots.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.11
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• pp.1044-1049
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• 2006

We reported on characteristics of the fluorescent OLED fabricated on commercial ITO/glass and BCS grown IZO/glass substrate, respectively. The amorphous IZO anode film grown by box cathode sputtering(BCS) exhibited similar electrical and optical characteristics to commercial ITO anode even though it was deposited at room temperature. In addition, the amorphous IZO anode showed higher workfunction (5.2 eV) than that of the commercial ITO anode (5.0 eV) after ozone treatment for 10 min. Furthermore, fluorescent OLED fabricated on amorphous IZO anode film showed improved current-voltage-luminance characteristics, external quantum efficiency and power efficiency en contrast with fluorescent OLED fabricated on commercial ITO anode film. It was thought that smooth surface and high workfunction of amorphous IZO anode lead to more efficient hole injection by reduction of interface barrier height between anode and organic layers.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.476-480
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• 2003

In this paper, we have performed 3-dimensional time-resolving measurement of the Ne light emitted from the cell of plasma display panel(PDP) as a function of the pressure using the scanned point detecting system. From the temporal behavior results, we could analyze the discharge behavior of panel with Ne-Xe(4%) mixing gas and 300 torr, 400 torr and 500 torr pressure. At the top view of panel, the discharge of 300 torr panel starts at the 634 ns and ends at the 722 ns. The emission duration time is about 90 ns. The discharge of 400 torr panel starts at the 682 ns and ends at the 786 ns. the emission duration time is about 100 ns. Also, the discharge of 500 torr panel starts at the 770 ns and ends at the 826 ns. the emission duration time is about 56 ns. The discharge moves from inner edge of cathode electrode to outer cathode electrode forming arc type. In the side view of 300 torr, 400 torr and 500 torr an emission shows that the light is detected up to 180${\mu}{\textrm}{m}$, 150${\mu}{\textrm}{m}$ and 70${\mu}{\textrm}{m}$ height of barrier rib and the emission distribution of the 300 torr is wider than 400 torr, 500 torr.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1361-1363
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• 1997

Zinc oxide-based MOV was fabricated with $SiO_2$ additive ranging from 0.5 to 4.0 mol%, and the microstructure and electrical characteristics were investigated. $Zn_2SiO_4$ phase formed by $SiO_2$ additive was distributed at ZnO grains, grain boundaries, and multiple grain junctions. As the content of $SiO_2$ additive increases, average grain size decreased from 40.6 to $26.9{\mu}m$ due to the Pinning effect by $Zn_2SiO_4$ at grain boundaries Breakdown voltage and nonlinear exponent increased, and leakage current decreased in the range of $11.2{\sim}6.14{\mu}A$ with an increasing $SiO_2$. Donor concentration and interface state density decreased, and barrier height increased in the range of $0.71{\sim}1.04eV$ with an increasing $SiO_2$. While, as the content of $SiO_2$ additive, apparent dielectric constant decreased, peak frequency of dissipation factor decreased in the range of $6.45{\times}10^5{\sim}3.00{\times}10^5Hz$, and dissipation peak was $0.31{\sim}0.22$ at Peak frequency.

• Journal of the Korean Ceramic Society
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• v.40 no.1
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• pp.5-10
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• 2003

Porous barium-strontium titanate ceramics were fabricated by adding corn- or potato-starch (are referred to as starch). The effect of sintering temperature on the microstructure and electrical properties of the porous ceramics was investigated. The room-temperature electrical resistivity of the barium-strontium titanate ceramics decreased with sintering temperature. The porosity and pore size were decreased and the grain size was increased with increasing the sintering temperature. The porosity and grain size of the barium-strontium titanate ceramics with corn-starch sintered at 1300 and 1450$^{\circ}C$ were 28.5, 22.6% and 3.2, 6.2 $\mu\textrm{m}$, respectively. The average pore sizes of the barium-strontium titanate ceramics with corn-starch sintered at 1300, 1400 and 1450$^{\circ}C$ were 0.5, 0.3 and 0.2 $\mu\textrm{m}$, respectively. The decrease in the room-temperature resistivity with increasing sintering temperature is attributed mainly due to the increase of grain size and the decrease of the electrical barrier height of grain boundaries as well as the partial decrease of porosity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.78-79
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• 2008

In this paper, poly 3C-SiC thin films were grown on $SiO_2$/Si by atmospheric pressure chemical vapor deposition (APCVD) using HMDS, $H_2$, and Ar gas at $1100^{\circ}C$ for 30 min, respectively. And then, palladium films were deposited on poly 3C-SiC by RF magnetron sputter. Thickness, uniformity, and quality of these samples were performed by SEM. Crystallinity and preferred orientationsof palladium were analyzed by XRD. And Pd/poly 3C-SiC schottky diodes were fabricated and characterized by current-voltage measurements. Its electric current density Js and barrier height voltage were measured as $2\times10^{-3}$ A/$cm^2$, 0.58 eV, respectively. And these devices operated about $350^{\circ}C$. From results, Pd/poly 3C-SiC devices are promising for high temperature hydrogen sensor and applications.