• Title/Summary/Keyword: Space charge layer

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Analysis of Electric Field Distribution and Characteristics of Volume Resistivity in HDPE/EVA Film for Recycling (재활용을 고려한 HDPE/EVA필름의 전계분포 및 체적저항특성 해석)

  • Lee, Hung-Kyu;Lim, Kee-Joe;Kim, Yong-Joo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.9
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    • pp.801-807
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    • 2008
  • Recently, CV, CN-CV and CNCV-W cable are used for HVDC transmission and distribution cable. However, XLPE which is used as insulation layer of power cable has thermosetting properties. It is very difficult to recycling. In this paper, we prepared HDPE/EVA film, which the blending ratio are 80:20, 70:30, 60:40, 50;50 respectively for the purpose of recycling. Main factor such as electric field distribution and its resistivity in insulation system affected on insulation performance and reliability for HVDC applications. Therefore, electric field distribution formed by space charge and characteristics of volume resistivity was currently investigated. We suggest the possibility of utilization for HVDC insulation layer from the results.

Finite Element Method (FEM) Study on Space Charge Effects in Organic Light Emitting Diodes (OLED)

  • Kim, Kwang-Sik;Hwang, Young-Wook;Won, Tae-Young
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.12 no.4
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    • pp.467-472
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    • 2012
  • In this paper, we present a finite element method (FEM) study on the space charge effects in organic light emitting diodes. The physical model covers all the key physical processes in OLEDs, namely charge injection, transport and recombination, exciton diffusion, transfer and decay as well as light coupling, and thin-film-optics. The exciton model includes generation, diffusion, and energy transfer as well as annihilation. We assumed that the light emission originates from oscillation which thus is embodied as exciton in a stack of multilayer. We discuss the accumulation of charges at internal interfaces and their signature in the transient response as well as the electric field distribution. We also report our investigation on the influence of the insertion of the emission layer (EML) in the bilayer structure.

A Basic Study on Electrification Phenomena of Synthetic Polymer Material (합성고분자재료의 대전현상에 관한 기초연구)

  • 이덕출;한상옥
    • 전기의세계
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    • v.28 no.10
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    • pp.48-54
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    • 1979
  • The electrification phenomena of polymerized materials is governed by the competitive processes of the charge generation and the charge dissipation. In this paper, The charged particles were supplied on the naked upper surface of the polyethylene film from a point corona discharge with a screen electrode which controls the potential difference across the film. The charging current with the corona charging was found to be larger than that obtained with the electric charging on the MIM structure and the discharge current was found to flow in the same direction as that of the charging current. these results can suggest that the charge injection occurs from the interface between the polethylene surface and the accumulated charge layer, the injected charge are trapped and the space charge is established.

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Electrical Conduction Mechanism in ITO/$Alq_3$/Al device structure (ITO/$Alq_3$/Al 소자 구조에서 전기 전도 메카니즘)

  • Chung, Dong-Hoe;Kim, Sang-Keol;Lee, Dong-Gyu;Lee, Joon-Ung;Hur, Sung-Woo;Jang, Kyung-Uk;Lee, Won-Jae;Song, Min-Jong;Kim, Tae-Wan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.531-532
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    • 2005
  • We have used ITO/$Alq_3$/Al structure to study electrical conduction mechanism in $Alq_3$ based organic light emitting diode. Current-voltage characteristics were measured at room temperature by varying the thickness of $Alq_3$ layer from 60 to 400nm. We were able to prove that there are three different mechanism depending on the applied voltage; Ohmic, SCLC (space-charge-limited current). and TCLC (trap-charge -limited current) mechanism.

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Electrical Conduction Mechanism in ITO/Alq3/Al Organic Light-emitting Diodes

  • Chung, Dong-Hoe;Lee, Joon-Ung
    • Transactions on Electrical and Electronic Materials
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    • v.5 no.1
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    • pp.24-28
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    • 2004
  • We have used ITO/Alq$_3$/Al structure to study electrical conduction mechanism in organic light-emitting diodes. Current-voltage-luminance characteristics were measured at room temperature by varying the thickness of Alq$_3$ layer from 60 to 400mm. We were able to confirm that there are three different mechanisms depending on the applied voltage region; ohmic, space-charge-limited current, and trap-charge-limit-current mechanism. And the maximum luminous efficiency was obtained when the thickness of Alq$_3$ layer is 200nm.

Conduction mechanism in organic light-emitting diode in ITO/PEDOT/PSS/TPD/Alq$_3$/LiAl structure (ITO/PEDOT/PSS/TPD/Alq$_3$/LiAl 구조의 유기 발광 소자에서 전도 메카니즘)

  • 정동회;김상걸;정택균;오현석;이원재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.198-201
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    • 2002
  • We have studied the temperature dependence of current-voltage and luminance-voltage characteristics of Organic Light Emitting Diodes(OLEDs). The OLEDS are based on the molecular compounds, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) as a hole transport, tris(8-hydroxyquinolinoline) aluminum(III) (Alq$_3$) as an electron transport, and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a buffer layer. The current-voltage and luminance-voltage characteristics were measured in the temperature range of 10[K] and 300[K]. A conduction mechanism in OLEDs has been interpreted in terms of space-charge-limited current(SCLC) and tunneling mechanism.

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Absence of Distinctively High Grain-Boundary Impedance in Polycrystalline Cubic Bismuth Oxide

  • Jung, Hyun Joon;Chung, Sung-Yoon
    • Journal of the Korean Ceramic Society
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    • v.54 no.5
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    • pp.413-421
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    • 2017
  • In this work, we studied a fluorite structure oxides: Yttria stabilized zirconia, (YSZ); Gd doped $CeO_2$ (GDC); erbia stabilized $Bi_2O_3$ (ESB); Zr doped erbia stabilized $Bi_2O_3$ (ZESB); Ca doped erbia stabilized $Bi_2O_3$ (CESB) in the temperature range of 250 to $600^{\circ}C$ using electrochemical impedance spectroscopy (EIS). As is well known, grain boundary blocking effect was observed in YSZ and GDC. However, there is no grain boundary effect on ESB, ZESB, and CESB. The Nyquist plots of these materials exhibit a single arc at low temperature. This means that there is no space charge effect on ${\delta}-Bi_2O_3$. In addition, impedance data were analyzed by using the brick layer model. We indirectly demonstrate that grain boundary ionic conductivity is similar to or even higher than bulk ionic conductivity on cubic bismuth oxide.

experiment and its upgrade with the large silicon charge detector

  • Lee, Jik;Nam, Ji-Woo;Park, Il-Hung;Yang, Jong-Man;Lee, Hye-Young;Na, Go-Woon;Jeon, Jin-A;Suh, Jung-Eun;Lim, Sun-In;Lee, Moo-Hyun;Seo, Eun-Suk
    • Bulletin of the Korean Space Science Society
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    • 2011.04a
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    • pp.20.2-20.2
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    • 2011
  • The NASA Antarctica balloon experiment CREAM has successfully collected the data of energetic cosmic rays during flights in past years. We will present the recent analysis results of the CREAM experiment. We will also report on the launch and recovery process of the latest flight. The silicon charge detector of the CREAM has played the key role in the precision measurement of the charge constitution of energetic cosmic rays. We proposed the upgrade of the CREAM experiment with the installment of a new large silicon charge detector on top of the CREAM instrument. The charge measurement of the large silicon detector with no material in front is expected to improve the accuracy of the CREAM charge measurement drastically when combined with the measurement of the existing double layer silicon detector. We will present the fabrication of the large silicon detector and its performance in the radiation source test as well as in the beam test.

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Energy Band Schemes in Organic Electroluminescent Devices Using Terbium Complexes Prepared by Vacuum Evaporation Method (진공 증착법에 의한 Terbium Comp1exes를 이용한 유기 전기 발광 소자의 에너지 밴드에 관한 연구)

  • 표상우;김옥병;이한성;최돈수;이승희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.582-588
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    • 1999
  • 정보화 사회의 발전과 함께 멀티미디어에 대한 관심이 집중되고 있으며, 점유 공간이 작고 가벼우며 대면적이 가능한 정보 표시 디스플레이에 대한 기술은 고부가가치 산업으로 인식되어 지고 있다. 이러한 정보 표시 디스플레이들 중, 전기 발광 소자 (Electroluminescence Display : ELD), 액정 표시 디스플레이 (Liquid Crystal Display LCD), 플라즈마 디스플레이 (Plasma Display Panel) 등의 대한 연구가 세계적으로 매우 활발하게 진행되고 있다. 본 연구에서는 란탄 계열의 금속 착 화합물인 Tb(ACAC)$_3$(Phen)과 Tb(ACAC)$_3$(Phen-Cl)를 이용해 다비이스를 제작한후 광학적 및 전기적 특성을 조사하였다. 또한 luminous efficiency와 cyclic voltametric 방법을 이용해 에너지 밴드로 두 발광 물질인 Tb(ACAC)$_3$(Phen)과 Tb(ACAC)$_3$(Phen-Cl)을 비교.분석하였다. 본 연구의 디바이스 구조를 보면 anode/hole transporting layer (HTL)/emitting material layer (EML)/electron transporting layer (ETL)/cathode와 같고 ETL를 aluminum-tris- (8-hydroxyquinoline) (Alq$_3$)와 bis(10-hydroxybenzo(h)quinolinato)beryllium (Bebq$_2$)를 사용하였으며 HTL 로 N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD)를 사용하였다.

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The structural and dielectric polarization characteristics of composite oxide material in $(Ba Ca)TiO_3$-Zn (복합산화물 $(Ba Ca)TiO_3$-ZnO의 구조적 및 유전분극 특성)

  • 홍경진;임장섭;정우성;민용기;김용주;김태성
    • Electrical & Electronic Materials
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    • v.10 no.3
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    • pp.239-246
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    • 1997
  • The ZnO is stabilize dielectric constant over a broad temperature range because its addition makes the relaxation time short. In this study, the composite oxide material (B $a_{0.85}$ $Ca_{0.15}$)Ti $O_{3}$ was mixed by ZnO additive material and the dielectric polarization characteristics was studied. The relative density was over 90[%] at all specimen in the structural characteristics. Among of the specimen, the relative density of (B $a_{0.85}$ $Ca_{0.15}$)Ti $O_{3}$ with ZnO (0.4mol) has a 95[%]. The grain size of composite oxide material with an increasing ZnO increased and it was 1.0[.mu.m]-1.22[.mu.m]. In the electrical characteristics, the charge and discharge current was increased by ZnO addition. The dielectric relaxation time was increased by space charge polarization at above 110[.deg. C] and the dielectric relaxation time was fixed by space charge polarization of para-dielectric layer at below 110[.deg. C]. The dielectric relaxation time was maximum when the grain size was small. The dielectric relaxation time is decreased with an additive material ZnO and interface polarization, existing void at the grain and grain boundary. The remnant polarization is increased and the coercive electric field is decreased by ZnO.

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