• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.104-108
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• 2012

Flexible organic thin film solar cell device with Bulk Hetero-Junction (BHJ) structure was fabricated with blended conjugated polymer of PCDTBT : $PC_{71}BM$ as active layer. Surface of ITO anode for the organic solar cell device was treated with ozone. The organic solar cell device with bare ITO showed short circuit current density ($J_{sc}$) of $8.2mA/cm^2$, open-circuit voltage ($V_{oc}$) of 0.73V, fill factor (FF) of 0.36, and power conversion efficiency (PCE) of 2.16%, respectively. The organic solar cell device with ozone treated ITO anode revealed distinctively improved performance parameters:$J_{sc}$ of $9.8mA/cm^2$, $V_{oc}$ of 0.82V, FF of 0.43, PCE(${\eta}$) of 3.42%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.200-203
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• 2007

Devices of junction barrier schottky(JBS) structure using 4H-SiC substrates with wide energy band gaps was designed and fabricated. As a measurement results, the device of reverse I-V characteristics was shown as more than 1000 V, its design optimum length of p-grid was $3{\mu}m$ space. In this paper, I-V characteristics was modeled by using of device fabricated process conditions parameters and it was extracted that the I-V property parameters, and it was compared and analyzed with between device parameters and model parameters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.3
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• pp.250-254
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• 2006

Hetero-junction sheet actuator composed of carbon nanotubes and $V_{2}O_5$ nanowires were demonstrated in a bimetal configuration. The successive filtration of $V_{2}O_5$ nanowire solution followed by carbon nanotube dispersed water solution in the same way produced a dark-gray colored sheet. A significant actuation was observed in sodium chloride electrolyte solution with a bending direction to the carbon nanotube side at the positive bias voltage against the copper counter-electrode. As the frequency of the applied voltage increased, the amplitudes decreased, indicating a rather slow response of the hetero-film actuator in the electrolyte solution. The hybrid structure enabled an easy fabrication of the film actuator with the enhanced efficiencies.

• Progress in Superconductivity
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• v.1 no.1
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• pp.31-35
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• 1999

We have fabricated and tested a simple circuit of the rapid single-flux-quantum(RSFQ) four-stage shift register using a single layer high-$T_c$ superconducting (HTS) $YBa_2Cu_3O_{7-x}$ (YBCO) thin film structure with 9 step-edge Josephson junctions. The circuit includes two read superconducting quantum interference devices(SQUID) and four stages. To establish a robust HTS RSFQ device fabrication process, we have focussed on the reproducible process of sharp and straight step-edge formation as well as the ratio of film thickness to step height, t/h. The spread of step-edge junction parameters was measured from each 13 junctions with t/h=1/3, 1/2, and 2/3 at various temperatures. We have demonstrated the simplified operation of the shift register at 65 K.

• Journal of the Korean Vacuum Society
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• v.21 no.4
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• pp.185-192
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• 2012

p-n junction temperature and thermal resistance of Light Emitting Diode (LED) package are affected by the chip size due to the change of the thermal density and the external quantum efficiency considering the heat dissipation through conduction. In this study, forward voltage was measured for two different size LED chips, 24 mil and 40 mil, which consist constitute 16-chip package. p-n junction temperature and thermal resistance were determined by thermal transient analysis, which were discussed in connection with the electrical characteristics of the LED chip and the structure of the LED package.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.562-567
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• 1996

A new lateral MOS controlled thyristor, named Shorted Anode LMCT(SA-LMCT), is proposed and analyzed by a two-dimensional device simulation. The device structure employs the implanted n+ layer which shorts the p+ anode together by a common metal electrode and provides a electron conduction path during turn-off period. The turn-off is achieved by not only diverting the hole current through the p+ cathode short but also providing the electron conduction path from the n-base into the n+ anode electrode. In addition, the modified shorted anode LMCT, which has an n+ short junction located inside the p+ anode junction, is also presented. It is shown that the modified SA-LMCT enjoys the advantage of no snap-back behavior in the forward characteristics with little sacrificing of the forward voltage drop. The simulation result shows that the turn-off times of SA-LMCT can be reduced by one-forth and the maximum controllable current density may be increased by 45 times at the expense of 0.34 V forward voltage drop as compared with conventional LMCT. (author). 11 refs., 6 figs., 1 tab.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.81-92
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• 1997

Rear floating junction cell (RFJC), using the buried contact technology, is capable of eliminating the efficiency limitations on the single sided cells by providing betterear surface passivation. The implementation of this structure, is simpler and lower in cost and therefore viable for commercial production. However, the contributions, due to damages in the two sets of grooves, to the total dark saturation current density has limited the achievable efficiency of the RFJC to only 21.5 %. This Paper reports on the efficiency estimates of RFJC using PC-1D.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.189-196
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• 1991

This paper is an illustration of the application of the reliability analysis to the transverse structure of a SWATH ship. The ultimate strength of plate members on the cross structure and upper part of strut are considered in the reliability analysis. The fatigue reliability analysis has been also carried out at the junction of cross structure, sponsors and strut. Included is also an example of the allowable fatigue damage level. Demonstrated is the reliability study of series system of which elements are the ultimate and fatigue failure as well. Doing this would be desirable to get a truer solution of the structural safety level. The paper ends with a brief summary of the present reliability study and same important points which may be useful at the design stage.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.357-357
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• 2012

The doping process of the solar cell has been used by furnace or laser. But these equipment are so expensive as well as those need high maintenance costs and production costs. The atmospheric pressure plasma doping process can enable to the cost reduction. Moreover the atmospheric pressure plasma can do the selective doping, this means is that the atmospheric pressure plasma regulates the junction depth and doping concentration. In this study, we analysis the atmospheric pressure plasma doping compared to the conventional furnace doping. the single crystal silicon wafer doped with dopant forms a P-N junction by using the atmospheric pressure plasma. We use a P type wafer and it is doped by controlling the plasma process time and concentration of dopant and plasma intensity. We measure the wafer's doping concentration and depth by using Secondary Ion Mass Spectrometry (SIMS), and we use the Hall measurement because of investigating the carrier concentration and sheet resistance. We also analysis the composed element of the surface structure by using X-ray photoelectron spectroscopy (XPS), and we confirm the structure of the doped section by using Scanning electron microscope (SEM), we also generally grasp the carrier life time through using microwave detected photoconductive decay (u-PCD). As the result of experiment, we confirm that the electrical character of the atmospheric pressure plasma doping is similar with the electrical character of the conventional furnace doping.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.147.2-148
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• 2016

Light management technology is very important for thin film solar cells, which can reduce optical reflection from the surface of thin film solar cells or enhance optical path, increasing the absorption of the incident solar light. Using proper light trapping structures in hydrogenated amorphous silicon (a-Si:H) solar cells, the thickness of absorber layers can be reduced. Instead, the internal electric field in the absorber can be strengthened, which helps to collect photon generated carriers very effectively and to reduce light-induced loss under long-term light exposure. In this work, we introduced a chemical etching technology to make honey-comb textures on glass substrates and analyzed the optical properties for the textured surface such as transmission, reflection and scattering effects. Using ray optics and finite difference time domain method (FDTD) we represented the behaviors of light waves near the etched surfaces of the glass substrates and discussed to obtain haze parameters for the different honey-comb structures. The simulation results showed that high haze values were maintained up to the long wavelength range over 700 nm, and with the proper design of the honey-comb structure, reflection or transmission of the glass substrates can be enhanced, which will be very useful for the multi-junction (tandem or triple junction) thin film a-Si:H solar cells.