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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Institute of Electrical and Electronic Material Engineers
Journal Basic Information
Journal DOI :
The Korean Institute of Electrical and Electronic Material Engineers
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Volume & Issues
Volume 23, Issue 12 - Dec 2010
Volume 23, Issue 11 - Nov 2010
Volume 23, Issue 10 - Oct 2010
Volume 23, Issue 9 - Sep 2010
Volume 23, Issue 8 - Aug 2010
Volume 23, Issue 7 - Jul 2010
Volume 23, Issue 6 - Jun 2010
Volume 23, Issue 5 - May 2010
Volume 23, Issue 4 - Apr 2010
Volume 23, Issue 3 - Mar 2010
Volume 23, Issue 2 - Feb 2010
Volume 23, Issue 1 - Jan 2010
Selecting the target year
A Study of the Thermal Characteristics of a Photovoltaic Device with Surface Texturization
Jung, Ji-Chul ; Moon, Kyoung-Sook ; Koo, Sang-Mo ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 509~512
DOI : 10.4313/JKEM.2010.23.7.509
The thermal distribution of 2D and 3D p-n photovoltaic diode structures with and without surface texturing has been studied. By analysis of the numerical simulation results of the I-V characteristics and lattice temperature distributions the effect of different texturing structures on the characteristics of silicon p-n photovoltaic devices has been studied systematically. The efficiency of the device having surface texturing shows more than ~2% enhancement compared to the reference devices which did not have texturing. In addition, the effect of the density of the texturing groove has been studied and it has been confirmed that the texturing structure not only improves the light trapping but also plays an important role in the heat radiation.
Optimization of 4H-SiC DMOSFETs by Adjustment of the Dimensions and Level of the p-base Region
Ahn, Jung-Joon ; Bahng, Wook ; Kim, Sang-Chul ; Kim, Nam-Kyun ; Jung, Hong-Bae ; Koo, Sang-Mo ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 513~516
DOI : 10.4313/JKEM.2010.23.7.513
In this work, a study is presented of the static characteristics of 4H-SiC DMOSFETs obtained by adjustment of the p-base region. The structure of this MOSFET was designed by the use of a device simulator (ATLAS, Silvaco.). The static characteristics of SiC DMOSFETs such as the blocking voltages, threshold voltages, on-resistances, and figures of merit were obtained as a function of variations in p-base doping concentration from
and doping depth from
. It was found that the doping concentration and the depth of P-base region have a close relation with the blocking and threshold voltages. For that reason, silicon carbide DMOSFET structures with highly intensified blocking voltages with good figures of merit can be achieved by adjustment of the p-base depth and doping concentration.
Characterization of Ag doped 0.9(Na
Lee, Kyoung-Soo ; Koh, Jung-Hyuk ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 517~520
DOI : 10.4313/JKEM.2010.23.7.517
piezoelectric ceramics doped with
(0-4 mol%) have been prepared by the conventional mixed oxide method. The structural and electrical properties were analyzed in order to find its potential applications. The crystal structure of 1-4 mol% Ag doped
lead free piezoelectric ceramics were investigated for several sintering temperatures (
) by the use of X-ray diffraction analysis. In order to analyze the effect of Ag dopants on the
ceramic, the diffraction intensity ratio of the (002) to (200) planes were calculated from the X-ray diffraction patterns of the ceramic samples.
A Study of the Dielectric Properties of the Silver-Tantalate-Niobate Thick Films
Lee, Ku-Tak ; Yun, Seok-Woo ; Kang, Ey-Goo ; Koh, Jung-Hyuk ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 521~524
DOI : 10.4313/JKEM.2010.23.7.521
Low loss perovskite niobates and tantalates have been placed on a short list of functional materials for future technologies. In this study, we fabricated Ag(Ta,Nb)
thick films on the
substrates by the screen printing method. The Ag(Ta,Nb)
powders were fabricated by the mixed oxide method. The sintering temperature and time were
and 2 hrs, respectively. The results of XRD analysis showed that the specimens employed in this study had the pesudo cubic structure. The dielectric permittivity and loss tangent of the films have been characterized from 1 kHz to 1 MHz. Also the dielectric permittivity and loss tangent were measured from 303 K to 393 K. The electrical properties of the film are also discussed.
Design and Fabrication of a Thin-Type Ultrasonic Motor
Kim, Jong-Wook ; Park, Choong-Hyo ; Chong, Hyon-Ho ; Jeong, Seong-Su ; Park, Tae-Gone ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 525~529
DOI : 10.4313/JKEM.2010.23.7.525
In this paper, the characteristics of a thin-type ultrasonic motor generating elliptical displacements analyzed by FEM are presented, and then fabrication of the motor is then described. The structure of the motor consists of sixteen ceramic pieces attached to the upper and bottom surfaces of an elastic body. The principle of the motor is to apply alternating voltages which have a 90 phase difference to the attached ceramics, and then elliptical displacements are generated at four edges of the elastic body. Then the rotor is moved by the elliptical displacements. In the case of a ceramic thickness of 1.5, the highest speed was obtained at 79 kHz. In the case of a ceramic thickness of 2 mm, the highest speed was obtained at 77.5 kHz. Consequently, the speed and torque of the ultrasonic motor (USM) increased linearly with increasing applied voltage.
Dynamic Transient Phenomena of a Proton Exchange Membrane Fuel Cell
Lee, Ying ; Choi, Yong-Sung ; Zhang, You-Sai ; Lee, Kyung-Sup ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 530~533
DOI : 10.4313/JKEM.2010.23.7.530
The proton exchange membrane fuel cell (PEMFC) holds great promise of clean power. However, in practical applications which use the PEMFC as the power source, the output voltage from the fuel cell undergoes a transient response especially during acceleration and deceleration. This paper presents the relationships between the charge curves of the internal voltage rise, discharge curves of the internal voltage drop, the voltage with a time constant
and finally, the load and time constant
, connected both in series and in parallel.
Comparison of Output and Radiation Quality of X-rays according to the Full-Wave Rectification Method and Dual-Voltage Rectification Method of an X-ray Generator
Kim, Tae-Gon ; Cheon, Min-Woo ; Park, Yong-Pil ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 534~538
DOI : 10.4313/JKEM.2010.23.7.534
X-ray systems for medical treatment use noninvasive procedures. Being capable of locally inspecting the inside of the body, X-ray systems are routinely used for basic diagnosis. X-ray systems to be used for medical purposes were originally made with a gas filled tube inside an induction coil in the initial stages of development but with this approach it becomes difficult to take a satisfactory picture through thick body sections, non invasively. However continued development made it possible to take non-invasive pictures of breasts, blood vessels and other body parts through thick body sections. Recently, high-voltage X-ray generators of more compact size, increased generation efficiency, and sophisticated output control have become possible. All of these features are made possible by the use of a high-frequency output from an inverter and a fast switching semiconductor device. In this paper, we describe a new X-ray generator operating with a resonant inverter in order to reduce switching loss and high frequency noise. In addition, in order to identify the differences amongst types of rectification, we have compared output and the quality of X-ray pictures obtained with full-wave rectification and dual-voltage rectification methods.
Highly Enhanced EL Properties of PF Copolymers with Pyrazole Derivatives
Kang, In-Nam ; Lee, Ji-Hoon ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 539~544
DOI : 10.4313/JKEM.2010.23.7.539
We have synthesized new blue electroluminescent polyalkylfluorene-based copolymers [poly(F-co-Py)x:y, where x:y = 99:1 or 95:5 mole ratios] containing the hole-injecting pyrazole derivative [3,3'-(4,6-bis(octyloxy)-1,3-phenylene)bis(1,5-diphenyl-4,5-dihydro-1H-pyrazole] through Ni(0) mediated polymerization, and their electroluminescent properties were investigated. Electroluminescent (EL) devices were fabricated with ITO / PEDOT:PSS (110 nm) / copolymers or PF homopolymer (80 nm) / Ca (50 nm) / Al (200 nm) configuration. Each EL device constructed from the copolymer exhibited significantly enhanced brightness and efficiency compared with a device constructed from the PF homopolymer. The EL device constructed with poly(F-co-Py)99:1 exhibited the highest luminous efficiency and brightness (0.95 cd/A and
, respectively). The achieved luminous efficiency was an excellent result, providing almost a 4-fold improvement on the efficiency obtainable with the a PF homopolymer device. This enhanced efficiency of the copolymer devices results from their improved hole injection and more efficient charge carrier balance, which arises from the HOMO level (~5.83 eV) of the poly(F-co-Py)99:1 copolymer, which is higher than that of the PF homopolyme (~5.90 eV).
Analysis of the Threshold Voltage Instability of Bottom-Gated ZnO TFTs with Low-Frequency Noise Measurements
Jeong, Kwang-Seok ; Kim, Young-Su ; Park, Jeong-Gyu ; Yang, Seung-Dong ; Kim, Yu-Mi ; Yun, Ho-Jin ; Han, In-Shik ; Lee, Hi-Deok ; Lee, Ga-Won ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 545~549
DOI : 10.4313/JKEM.2010.23.7.545
Low-frequency noise (1/f noise) has been measured in order to analyze the Vth instability of ZnO TFTs having two different active layer thicknesses of 40 nm and 80 nm. Under electrical stress, it was found that the TFTs with the active layer thickness of 80 nm shows smaller threshold voltage shift (
) than those with thickness of 40 nm. However the
is completely relaxed after the removal of DC stress. In order to investigate the cause of this threshold voltage instability, we accomplished the 1/f noise measurement and found that ZnO TFTs exposed the mobility fluctuation properties, in which the noise level increases as the gate bias rises and the normalized drain current noise level(
) of the active layer of thickness 80 nm is smaller than that of active layer thickness of thickness 40 nm. This result means that the 80 nm thickness TFTs have a smaller density of traps. This result correlated with the physical characteristics analysis performmed using XRD, which indicated that the grain size increases when the active layer thickness is made thicker. Consequently, the number of preexisting traps in the device increases with decreasing thickness of the active layer and are related closely to the
instability under electrical stress.
Efficient Top-Emitting Organic Light Emitting Diode with Surface Modified Silver Anode
Kim, Sung-Jun ; Hong, Ki-Hyon ; Kim, Ki-Soo ; Lee, Ill-Hwan ; Lee, Jong-Lam ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 550~553
DOI : 10.4313/JKEM.2010.23.7.550
The enhancement of quantum efficiency using a surface modified Ag anode in top-emitting organic light emitting diodes (TEOLEDs) is reported. The operation voltage at the current density of
of TEOLEDs decreased from 9.3 V to 4.3 V as the surface of anode coated with
layer. The work function of these structures were quantitatively determined using synchrotron radiation photoemission spectroscopy. Secondary electron emission spectra revealed that the work function of the Ag/
structure is higher by 0.6 eV than that of Ag. Thus, the
structure acts as a role in reducing the hole injection barrier by about 0.6 eV, resulting in a decrease of the turn-on voltage of top-emitting light emitting diodes.
Frequency Spectrum Analysis of Series Arc and Corona Discharges
Kil, Gyung-Suk ; Jung, Kwang-Seok ; Park, Dae-Won ; Kim, Sun-Jae ; Han, Ju-Seop ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 554~559
DOI : 10.4313/JKEM.2010.23.7.554
In this paper, we analyzed the frequency spectrum of radiated electromagnetic pulses generated by series arc- and corona- discharges as a basic study to develop an on-line diagnostic technique for power facilities installed inside closed-switchboards. To simulate series arc and corona discharges, five types of electrode system which consists of needle and plane electrodes were arranged. The experiment was carried out in an electromagnetic shielding room, and the measurement system consists of an ultra log antenna and an EMI receiver. From the experimental results, the frequency spectrum exists in ranges from 30 MHz to 2 GHz for a series arc discharge and 30 MHz to 1.2 GHz depending on defects for a corona discharge. The peak frequency of the series arc- and corona- discharges were 100 MHz to 160 MHz and 40 MHz to 80 MHz, respectively.
A Study of the Slim Design of Overhead Transmission Tower
Lee, Jung-Won ; Lee, Won-Kyo ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 560~565
DOI : 10.4313/JKEM.2010.23.7.560
This paper presents the design factor of an overhead transmission tower structure in order to reduce the tower weight. The behaviour of transmission tower structures are affected by the horizontal angle of the tower structure, the equivalent wind pressure group, the slope of the main post of the tower, the separation of the internode and the use of high-strength materials in their construction. Tower weight can be reduced by approximately 30% reduce weight by means of optimal design based on a consideration of all the above factors. In addition, the design of the foundation of the tower with the shear key installation to increase horizontal support together with a modified angle of inclination to the ground can reduce by about 37% the amount of concrete used during construction. The area of ground disturbed by the construction of the tower foundation can thus be reduced by approximately 33%. Therefore it is possible to build an environmently-friendly T/L tower with the mechanical properties of existing towers.
The Electro-Optic Properties of Ferroelectric P(VDF-TrFE) LB Films
Kwak, Eun-Hwi ; Jung, Chi-Sup ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 566~570
DOI : 10.4313/JKEM.2010.23.7.566
Electro-optic modulators based on 25 monolayer langmuir-blodgett films of vinylidene fluoride and trifluoroethylene, P(VDF-TrFE), were fabricated. The LB films were prepared by transferring the monolayers on to an ITO coated glass with a surface pressure of 5 dyne/cm by use of the langmuir-schaefer deposition method. Measurement of the electro-optic coefficient has been carried out using a simple reflection techique. The E/O coefficient was found to be 154.9 pm/V and that value remained stable for at least 50 days.
Analysis of the Formation of Rear Contact for Monocrystalline Silicon Solar Cells
Kwon, Hyuk-Yong ; Lee, Jae-Doo ; Kim, Min-Jeong ; Lee, Soo-Hong ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 571~574
DOI : 10.4313/JKEM.2010.23.7.571
Surface recombination loss should be reduced for high efficiency of solar cells. To reduce this loss, the BSF (back surface field) is used. The BSF on the back of the p-type wafer forms a p+layer, which prevents the activity of electrons of the p-area for the rear recombination. As a result, the leakage current is reduced and the rear-contact has a good Ohmic contact. Therefore, the open-circuit-voltage (Voc) and fill factor (FF) of solar cells are increased. This paper investigates the formation of the rear contact process by comparing aluminum-paste (Al-paste) with pure aluminum-metal(99.9%). Under the vacuum evaporation process, pure aluminum-metal(99.9%) provides high conductivity and low contact resistance of
, but It is difficult to apply the standard industrial process to it because high vacuum is needed, and it's more expensive than the commercial equipment. On the other hand, using the Al-paste process by screen printing is simple for the formation of metal contact, and it is possible to produce the standard industrial process. However, Al-paste used in screen printing is lower than the conductivity of pure aluminum-metal(99.9) because of its mass glass frit. In this study, contact resistances were measured by a 4-point probe. The contact resistance of pure aluminum-metal was
and that of Al-paste was
. Then the rear contact was analyzed by scanning electron microscope (SEM).
Application of a Selective Emitter Structure for Ni/Cu Plating Metallization Crystalline Silicon Solar Cells
Kim, Min-Jeong ; Lee, Jae-Doo ; Lee, Soo-Hong ;
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 23, issue 7, 2010, Pages 575~579
DOI : 10.4313/JKEM.2010.23.7.575
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%.