• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.590-590
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• 2012

A transparent conducting oxide (TCO) layer was applied in crystalline Si (c-Si) solar cells without use of the conventional SiNx-coating. A high quality indium-tin-oxide (ITO) layer was directly deposited on an emitter layer of a Si wafer. Three different types of emitters were formed by controlling the phosphorous diffusion condition. A light-doped emitter forming a thinner emitter junction showed an improved photoconversion efficiency of 14.1% comparing to 13.2% of a heavy-doped emitter. This was induced by lower recombination within a narrower depletion region of the light-doped emitter. In the aspect of light management, the intermediate refractive index of ITO is effective to reduce the light reflection leading the enhanced carrier generation in a Si absorber. For the electrical aspect, the ITO layer serves as an efficient electrical conductor and thus relieves the burden of high contact resistance of the light-doped emitter. Additionally, the ITO works as a buffer layer of Ag and Si and certainly prevents the shunting problem of Ag penetration into Si emitter region. It discusses an efficient design scheme of TCO-embedded emitter Si solar cells.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.732-738
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• 2014

Combined optical simulation of the ray-tracing technique and the finite difference time domain method was used to investigate the effect of the emitter orientation and the photonic crystal layer on the outcoupling efficiency (OCE) of bottom-emission type organic light emitting diodes (OLEDs). The OLED with a horizontal emitter exhibited an opposite interference effect to that of one with a vertical emitter, which suggested that the OCE would be very sensitive to the emitter orientation at a fixed emitter-cathode distance. The OLED with a horizontal emitter exhibited much larger OCE than that with a vertical emitter did, which was due to the substantial difference in the radiation pattern along with the different coupling with the surface plasmon excitation. The OCE with a horizontal emitter was increased by approximately 1.3 times by inserting a photonic crystal layer between the indium tin oxide layer and the glass substrate. The present study suggested that appropriate control of the emitter orientation and its combination to other outcoupling structures could be used to enhance the OCE of OLEDs substantially.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2899-2905
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• 2011

We have demonstrated that TPyPA can be used as an efficient multi-functional material for OLEDs; hole transporting material (HTL), blue and white-light emitter. The device based on TPyPA as the HTL exhibited an external quantum efficiency of 1.7% and a luminance efficiency of 4.2 cd/A; these values are 40% higher than the external quantum efficiency and luminance efficiency of the NPD-based reference device. The device based on TPyPA as a blue-light emitter exhibited an external quantum efficiency of 4.2% and a luminance efficiency of 5.3 $cdA^{-1}$ with CIE coordinates at (0.16, 0.14), the device based on TPyPA as a white-light emitter exhibited an external quantum efficiency of 3.2% and a luminance efficiency of 7.7 $cdA^{-1}$ with CIE coordinates at (0.33, 0.39). Also, TPyPA-based organic solar cell (OSC) exhibited a maximum power conversion efficiency of 0.35%. TPyPA-based organic thin-film transistors (OTFTs) exhibited highly efficient field-effect mobility (${\mu}_{FET}$) of $1.7{\times}10^{-4}cm^2V^{-1}s^{-1}$, a threshold voltage ($V_{th}$) of -15.9 V, and an on/off current ratio of $8.6{\times}10^3$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.11
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• pp.546-550
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• 2002

In this paper, Heterojunction phototransistors(HPT's) with an optically transparent ITO emitter contacts were fabricated. The ITO ohmic contacts were realized by employing thin imdium layer between the ITO and $n^+$-InP layers. The ITO contact was annealed at $250^{\circ}C$. The specific contact resistance of about $6.6{\times}10^{-4}{\Omega}cm^2$ was measured by use of the transmission line model (TLM). Heterojunction bipolar transistors (HBTs) having the same device layout were fabricated to compare with HPTs. The DC characteristics of the InP/InGaAs HPT showed the similar electrical characteristics of the HBT. Emitter contact resistance($R_E$) of about $6.4{\Omega}$ was extracted, which was very similar to that of the HBT. The optical characteristics of HPT's were generated by illuminating the device with light from $1.3{\mu}m$ light. It showed that HPT's can be controlled optically.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.21-24
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• 2003

The understanding of the mechanism of device degradation has been accomplished recently, for devices using $AlQ_3$ electron transport and emitter molecule. In this presentation the experimental evidence for the degradation mechanism of $AlQ_3$ based devices will be reviewed, showing that the hypothesis of an unstable $AlQ_3^+$ cation explains a large amount of experimental data. This hypothesis, however, explains not only the room temperature device degradation in time but also sheds light on temperature stability of OLEDs. Dependence of half-life of a series of devices with an emitter layer composed of a mixture of $AlQ_3$ and different hole transport molecules (mixed emitter layer) will be discussed when they are operated at elevated temperatures. These results can also be explained in the framework of an unstable $AlQ_3^+$ species. An OLED structure containing a doped mixed emitter layer will be described, which shows extraordinary stability, half-life of 1200 hours at operating temperature of 70 C and initial luminance of 1650 $cd/m^2$. We will also discuss a novel Black $Cathode^{TM}$ OLED with reduced optical reflectivity, which is also stable at elevated temperatures. The new cathode utilizes a conductive light-absorbing layer made of a mixture of metals and organic materials.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.2099-2106
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• 2003

In this paper, a novel fast response NDIR analyzer (FRNDIR), which uses an electrically pulsed semiconductor emitter and dual type PbSe detector for the PPM-level detection of carbon dioxide (CO$_2$) at a wavelength of 4.28 $\mu\textrm{m}$, is described. Modulation of conventional NDIR energy typically occurs at 1 to 20 Hz. To achieve real time high-speed measurement, the new analyzer employs a semiconductor light emitter that can be modulated by electrical chopping. Updated measurements are obtained every one millisecond. The detector has two independent lead selenide (PbSe) with IR band pass filters. Both the emitter accuracy and the detector sensitivity are increased by thermoelectric cooling of up to -20 degrees C in all semiconductor devices. Here we report the use of semiconductor devices to achieve improved performance such that these devices have potential application to CO$_2$ gas measurement and, in particular, the measurement of fast response CO$_2$ concentration at millisecond level.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.23-26
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• 2011

New organic light-emitting diodes with structure of ITO/DNTPD/TAPC/$Bebq_2/Bebq_2$:RP-411/ET-137/LiF/Al using the selective doping of 5% RP-411 in a single $Bebq_2$ host in the two wavelength(green, red) emitter formation were proposed and characterized. In the experiments, with a 300${\AA}$-thick undoped emitter of $Bebq_2$, three kinds of devices with different thicknesses of 30${\AA}$, 40${\AA}$ and 50${\AA}$ in the doped emitter of $Bebq_2$:RP-411 were fabricated. The electroluminescent spectra showed two peak emissions at the same wavelengths of 511 nm and 622 nm for the fabricated devices. When the device with a 30${\AA}$-thick doped emitter is referred as "D-1", the device with a 40${\AA}$-thick doped emitter is referred as "D-2" and the device with a 50${\AA}$-thick doped emitter is referred as "D-3", the relative intensity of 622 nm to 511 nm at two wavelength peaks was higher in the D-2 and the D-3 than in the D-1. The devices of D-1, D-2 and D-3 showed the color coordinates of (0.43, 0.46), (0.46, 0.44) and (0.48, 0.43) on the CIE chart, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.575-579
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• 2010

The technologies of Ni/Cu plating contact is attributed to the reduced series resistance caused by a better contact conductivity of Ni with Si and the subsequent electroplating of Cu on Ni. The ability to pattern narrower grid lines for reduced light shading was combined with the lower resistance of a metal silicide contact and an improved conductivity of the plated deposit. This improves the FF (fill factor) as the series resistance is reduced. This is very much requried in the case of low concentrator solar cells in which the series resistance is one of the important and dominant parameter that affect the cell performance. A Selective emitter structure with highly dopeds regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing In this paper the formation of a selective emitter, and the nickel silicide seed layer at the front side metallization of silicon cells is considered. After generating the nickel seed layer the contacts were thickened by Cu LIP (light induced plating) and by the formation of a plated Ni/Cu two step metallization on front contacts. In fabricating a Ni/Cu plating metallization cell with a selective emitter structure it has been shown that the cell efficiency can be increased by at least 0.2%.

• Korean Journal of Materials Research
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• v.16 no.4
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• pp.231-234
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• 2006

To obtain balanced white-emission and high efficiency of the organic light-emitting diodes (OLEDs), a deep blue emitter made of N,N'-diphenyl-N,N'-bis(1-naphthyl)- (1,1'-biphenyl)-4,4'-diamine (NPB) emitter and a new red emitter made of the Bis(2,4 -dimethyl-8-quinolinolato)(triphenylsilanolato)aluminum(III) (24MeSAlq) doped with red fluorescent 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H -pyran (DCJTB) were used and the device was tuned by varying the thickness of the DCJTB-doped 24MeSAlq and $Alq_3$. For the white OLED with 10 nm thickness DCJTB (0.5%) doped 24MeSAlq and 45 nm thick $Alq_3$, the maximum luminance of about 29,700 $Cd/m^2$ could be obtained at 14.8 V. Also, Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.32, 0.28) at about 100 $Cd/m^2$, which is very close to white light equi-energy point (0.33, 0.33), could be obtained.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.151-154
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• 2008

The field emission lamps have the advantages to their cold cathode-characteristic and the eco-friendly, We realized that the dual emitter system showed very simple structure which gate and cathode electrodes are formed on the same glass surface. In this paper, we reported the properties of dual emitters depended on variation of gate width and spacing for optimum panel structure. In combination of dual emitter structure and bi-polar driving, electron beam spreads more than normal gate structure or diode structure, and emission uniformity increased in dual emitter structure at 5"-diagonal.