In this study, the electrical characteristics of the nickel (Ni)/carbon nanotube (CNT)/SiO2structures were investigated in order to analyze the mechanism of CNT in MOS device structures. We fabricated 4H-SiC MOS capacitors with or without CNTs. CNT was dispersed by isopropyl alcohol. The capacitance-voltage (C-V) and current-voltage (I-V) are characterized. Both devices were measured by Keithley 4200 SCS. The experimental flatb and voltage (VFB) shift was positive. Near-interface trap charge density (Nit) and negative oxide trap charge density (Nox) value of CNT embedded MOS capacitors was less than that values of reference samples. Also, the leakage current of CNT embedded MOS capacitorsis higher than reference samples. It has been found that its oxide quality is related to charge carriers and/or defect states in the interface of MOS capacitors.

This paper was showed latch up characteristics of super junction power MOSFET by parasiticthyristor according to trench etch angle. As a result of research, if trench etch angle of super junction MOSFET is larger, we obtained large latch up voltage. When trench etch angle was 90°, latch up voltage was more 50 V. and we got 700 V breakdown voltage. But we analyzed on resistance. if trench etch angle of super junction MOSFET is larger, we obtained high on resistance. Therefore, we need optimal point by simulation and experiment for solution of trade off.

n this paper, in order to develop outstanding Pb-free composition ceramics, the Fe2O3-doped(Na0.525K0.443Li0.037)(Nb0.883Sb0.08 Ta0.037)O3 + 0.3 wt% Bi2O3 + x wt% Fe2O3 (x= 0∼1.0 wt%)(abbreviated as NKL-NST) lead-free piezoelectric ceramics have been synthesized using the ordinary solid state reaction method. The effect of Fe2O3-doping on their microstructure and electrical properties were investigated. XRD diffraction pattern studies confirm that Fe2O3 completely diffused into the NKL-NSTlattice to form a new stable soild solution with Fe3+ entering the Nb5+, Sb5+ and Ta5+ of B-site. And, phase structure of all the ceramics exhibited pure perovskite phase and no secondary phase was found in the ceramics. The ceramics doped with 0.6 wt% Fe2O3 have the optimum values of piezoelectric constant(d33), planar piezoelectric coupling coefficient(kp) and mechanical quality factor(Qm) : d33= 233[pC/N], kp= 0.44, Qm= 95. These results indicate that the (Na0.525K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3 +0.3 wt%Bi2O3 + 0.6 wt% Fe2O3 ceramic is a promising candidate for lead-free piezoelectric ceramics.

Thermoelectric materials have been the topic of intensive research due to their unique dual capability of directly converting heat into electricity or electrical power into cooling or heating. Bismuth telluride (Bi2Te3) is the best-known commercially used thermoelectric material in the bulk form for cooling and power generation applications In this work we focus on the large scale synthesis of nanostructured undoped bulk nanostructured Bi2Te3 materials by employing a novel bottom-up solution-based chemical approach. Spark plasma sintering has been employed for compaction and sintering of Bi2Te3 nanopowders, resulting in relative density of g·cm-3 while preserving the nanostructure. The average grain size of the final compacts was obtained as 200 nm after sintering. An improved NS bulkundoped Bi2Te3 is achieved with sintered at 400℃ for 4 min holding time.

Electrode pattern effects on the capacitive humidity sensor were investigated. The fabrication of the capacitive humidity sensor was formed with three steps. The bottom electrode was formed on the silicon substrate with Pt/Ti thin layer by using shadow mask and e-beam evaporator. The photosensitive polyimide was formed on the bottom electrode by using photolithography process as a humidity sensitive thin film. The upper electrode was formed on the polyimide thin film with Pt/Ti thin layer by using e-beam evaporator and lift-off method. Three electrode patterns, such as circle, square, and triangle pattern, were used and changed the sizes to investigate the effects. The capacitances of the sensors were decreased 622 to 584 pF with the area decreament of patterns 250,000 to 196,250 μm2. From these results, a capacitive humidity sensor with photo sensitive polyimide is expected to be applied to a high sensitive humidity sensor.

We synthesized new materials of Zn(HPB)2 and Ir-complexes as blue or red emitting material. We fabricated white Organic Light Emitting Diodes (OLED) by using Zn(HPB)2 for the blue emitting layer, Ir-complexes for the red emitting layer and Alq3 for the green emitting layer. We fabricated white OLED by using double emitting layers of Zn(HPB)2:Ir-complexes and Alq3. The doping rate of Ir-complexes was varied, such as 0.2%, 0.4%, 0.6%, and 0.8%, respectively. When the doping rate of Zn(HPB)2:Ir-complexes was 0.6%, white emission was achieved. The Commission Internationale de l`Eclairage (CIE) coordinates of the white emission was (0.322, 0.312).

This study used the heat conductive silicone rubber sample of 0.95 mm thickness to research the properties of current by changing voltage. When the 1, 10, 30, 60, and 90 minute have passed, the running current has been measured through the applied voltage range of 200 V～800 V on setting temperature of 110℃～170℃. As the temperature increased in applied voltage of 800 V, so did the current value according to time in proportion to the increasing temperature. In an analysis of FT-IR (fouriertransform infrared) spectrum, the hydroxyl radicals group(O-H) was created by effects of the hydrogen that methyl group is eliminated by addition of the cross-linking agent peroxide.

3 mol% Co-added Ni(OH)2 fine powders, which showed β-phase, as positive electrode materials have been fabricated using NiSO4；6H2O aqueous solution by ultrasonic spray-chemical precipitation and subsequent hydrothermal method, and sheet-like Ni nanopowder was fabricated by mechano-chemical reduction method. The addition effects of the sheet-like Ni nanopowder on the electrochemical properties of the positive electrode in Ni-Zn Redox flow battery were investigated. Impedance spectroscopy revealed that the addition of the sheet-like Ni nanopowder resulted in decrease in the electrical resistivity; 10 wt.% addition reduced the electrical properties by a fifth. Cyclic voltammetry showed the addition of the sheet-like Ni nanopowder resulted in decrease in the potential difference of oxidation and reduction; this means the increase in the reversability for electrode reduction. Charge/discharge measurement confirmed that the addition of the sheet-like Ni nanopowder resulted in the increase in the discharge efficiency.

AlNO multi-layer thin films on aluminum substrates were prepared by DC reactive magnetron sputtering method. Al2O3/AlNO(LMVF)/AlNO(HMVF)/Al/substrate of 4 multi-layer has been prepared in an Ar and (N2+O2) gas mixture, and Al2O3 of top layer is anti-reflection layer on double AlNO(LMVF)/AlNO(HMVF) layers and Al metal of infrared reflection layer. In this study, the roughness and surface properties of AlNO thin films were estimated by field emission scanning electron microscopy(FE-SEM). The grain size of AlNO thin films increased with increasing sputtering power. The composition of thin films has been systematically investigated using electron probe microanalysis(EPMA). The optical properties with wavelength spectrum were recorded by UV-Vis-NIR spectrophotometry at arange of 200～1,500 nm. The absorptance of AlNO films shows the increasing trend with swelling(N2+O2) gas mixture in HMVF and LMVF deposition. The excellent optical performance showed above98% of absorptance in visible wavelength region.

The heat dissipation conditions of high-power 5 watt LEDs-based searchlight modules were optimized with varying LED bar’shape, materials, and ambient temperature. The LED junction temperature was estimated by using Computational Fluid Dynamics simulation. The optimal heat dissipation conditions were found as follows; LED bar’ shape: L=80 mm, W=4 mm, t=10 mm, copper material, LED junction temperature of 116.6℃, ambient temperature of 50℃, total mass of 184 g, and shadowing area of 320 mm2. The difference between the junction temperatures of our fabricated and simulated LEDs-based searchlight modules is about 3℃, which confirms the validity of our thermal simulation results.

The interest in development on luminaires which are available up to -52℃ is surging as demands in vessels navigating a north pole route increase. A conventional incandescent lamp used invessels is operated stably at -52℃, but many countries including Korea have eliminated the use of incandescent lamps gradually because of its low luminous efficacy. In this paper, therefore, to develop the LED luminaires with high-efficiency, long lifetime that enables to substitute for incandescent lamp, it has studied about cryogenic characteristics of LED packages, bulbs, driving circuit and power supply. This experiments were carried out according to standards IEC 60945-8.4.1. Temperature range is from -60℃ to25℃, and the light output depending on ambient temperature. It showed that, based on 25℃, light output of a CFL decreased by 80% of CFL at -20℃ while each increased 12% of LED bulbs and 16∼19% of LED packages at -60℃.

Recently, LED lighting fixtures for crosswalk become popular in order to recognize the pedestrians at crosswalk, which can enhance the safety of the pedestrian at crosswalk. However, there are several problems related to the LED lighting fixtures for crosswalk, such as a lot of energy consumption due to a constant illumination during night and glaring of pedestrians at the opposite side of crosswalk. In this study, in order to overcome these problems, we have investigated a novel LED lighting fixture for crosswalk, which has two modules with different angles (60°, 120°). Illuminance of min and max at four-line city street crosswalk shown 50 Lux, 125 Lux, respectively. Illuminance of min and max at eight-line city street crosswalk shown 150 Lux, 200 Lux, respectively. Simulation investigation was optimized design using optical program. Prototype was verified measurement by goniometer system.