• Title/Summary/Keyword: D.C. conduction

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INVESTIGATIONS OF CONDUCTION MECHANISM OF ORGANIC MOLECULES USED AS BUFFER HOLE INJECTING LAYER IN OLEDS

  • Shekar, B. Chandar;Rhee, Shi-Woo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.966-969
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    • 2003
  • Thin film capacitors with Al-Polymer-Al sandwich structure were fabricated. The bottom and top aluminium (Al) electrodes were deposited by vacuum evaporation and copper phthalocyanine (CuPc), polyaniline-emeraldine base (Pani-EB) and cobalt phthalocyanine/polyaniline - emeraldine base (CoPc /Pani-EB) blend films (which can be used as buffer hole injection layer in OLEDs) were deposited by spin coating technique. X-ray diffractograms indicated amorphous nature of the polymer films whose thicknesses were measured by capacitance and Rutherford Backscattering Spectrometry (RBS) methods. AC conduction studies revealed that the conduction mechanism responsible in these films is variable range hopping of polarons. From D.C conduction studies, it is observed that, the nature of conduction is ohmic in the lower fields and at higher fields the dominating D.C conduction is of Poole-Frenkel type.

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A study on conduction current and D.C. breakdown characteristics in dielectric liquids (절연유의 도전전류와 직류절연파괴특성에 관한 연구)

  • 서국철
    • 전기의세계
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    • v.30 no.4
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    • pp.231-236
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    • 1981
  • It has been known that D.C. breakdown Voltage is lower than A.C. breakdown Voltage in insulatingoil, but there are still many unvivid points at electric conduction in breakdown or under of high electric field. This study measured the electric current-electric field characteristics (I-E characteristics) and the breakdown Voltage under of D.C. electric field of insulating oil using the system of electrodes that are near the Uniform electric field with a result. I can study, electric conduction in area of high electric field depends upon the Schottky effect. The liquidity of breakdown electric field takes place by the local concentration of electric field. The longer gap is and the more electric current is the more breakdown Voltage decreased. There are not almost the change of electric current-electric field characteristics by materials of electrode.

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A Study on the Electrical Properties of Amorphous Sb-Bi-Te Thin Films (비정질 Sb-Bi-Te 박막의 전기적 특성에 관한 연구)

  • ;;D. Mangalaraj
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.3
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    • pp.220-226
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    • 2002
  • Amorphous $Sb_{2-x}Bi_xTe_3$ (x = 0.0, 0.5 and 1.0) thin films were prepared by vacuum evaporation. The resistivity of 7he films decreases from 1.4{\times}10^{-2}$ to $8.84{\times}10^{-5}\Omega cm$ and the type of conductivity changes from p to n with the increase of the x value of the films. D.C. conduction studies on these films ate performed at various electric fields in the temperature range of 303-403 K. At low electric fields, two types of conduction mechanisms, i.e. the variable range hopping and the phonon assisted hopping are found to be responsible for the conduction, depending upon the temperature. The activation energy decreases from 0.082 to 0.076 eV in the temperature range of 303-363 K and from 0.47-0.456 eV in the second range of 363-403 K, indicating the shift of the Fermi level towards the conduction band edge and hence the change of the conduction from P to n type with the increase of the Bi concentration. Poole-Frankel emission dominates at high fields. The shape of the potential well of the localized centre is deduced and the mean free path of the charge carriers is also calculated.

The Electrical Characteristics of Amorphous $Te_{80}Se_{10}Sb_{10}$ Thin Film (비정질$Te_{80}Se_{10}Sb_{10}$ 박막의 전기적 특성)

  • 김흥석;이영종;정홍배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.238-241
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    • 1996
  • In this paper, we investigated the electrical characteristics which is d.c. and a.c. conductivity of the amorphous Te$_{80}$Se$_{10}$Sb$_{10}$thin film prepared by thermal evaporation. As the results, the d.c. conduction mechanism was followed thermally activated conduction and from the data of d.c. conductivity, the acti-vation energy and mobility gap were obtained. the d.c. conductivity was increased with temperature and a.c. conductivity also was increased with temperature and frequency. It can consider that the annealing is indispensable for higher conductivity since the activation energy decreased but d.c. and a.c. conductivity increased with annealing.aling.

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The Electrical Conduction Characteristics of Silicone oils due to Viscosity Variation (점도변화에 따른 실리콘유의 전기전도특성)

  • 조경순;홍진웅;신종열;이충호;이수원
    • Electrical & Electronic Materials
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    • v.10 no.9
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    • pp.945-951
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    • 1997
  • Inorder to investigated electrical conduction characteristics of silicone oils due to viscosity variation we studied the electrical conduction properties at temperature range of 10~110[$^{\circ}C$] and electrical field from 1 to 1.33$\times$10$^4$[V/cm] The viscosity of used specimens was low viscous(1, 2, 5[cSt]) silicone oils. It was shown the ohmic conduction characteristics in low temperature and low field by Ion dipole and humidity included specimen. And we known the conduction mechanism due to electron injection by Schottky's effect in the high temperature an d high field region.

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The Characteristics of Conduction rind Switching Voltage for As-Ge-Te Memory Switching Device (As-Ge-Te 메모리 스위칭 소자의 전도 및 스위칭 전압 특성)

  • 이병석;이현용;이영종;정흥배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1995.11a
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    • pp.67-70
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    • 1995
  • Amorpous As$\sub$10/Ge$\sub$15/Te$\sub$75/ device shows the memory switching characterisite under d.c. bias. In bulk material, a-As$\sub$10/Ge/sub15/Te$\sub$75/s switching voltage range is above 100 volts. Our purposes in this gaudy are decreasing a switching threshold voltage, finding the properties of d.c., a.c. conduction, and the characterisitics of switching threshold voltage fur a-As$\sub$10/Ge$\sub$15/Te$\sub$75/. As the results, the d.c.and a.c. conductivities increase with temperature. From the data of conductivity, various electrical and physical properties are obtained experimentally. The switching threshold voltages decrease with increasing annealing temperature and time, but increase with increasing film thickness and distance of electrode for d.c. bias.

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Characteristics of Electrical Conduction of OLED with Various Temperature and thickness (온도와 두께 변화에 따른 유기 발광 다이오드의 전기전도 특성)

  • Lee, D.G.;Oh, Y.C.;Jung, D.H.;Lee, H.S.;Jang, K.U.;Kim, C.H.;Hong, J.W.;Kim, T.W.;Lee, J.U.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.516-517
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    • 2005
  • We made use of $Alq_3$ which is the representative light-emitting material. Electric conduction mechanism were analyzed in this paper. We have also measured current density-thickness-voltage characteristics with thickness variation from 60 to 400 nm. We analyzed the low electric and the high electric field in theoretically.

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A Review of SiC Static Induction Transistor (SIT) Development for High-Frequency Power Amplifiers

  • Sung, Y.M.;Casady, J.B.;Dufrene, J.B.
    • KIEE International Transactions on Electrophysics and Applications
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    • v.11C no.4
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    • pp.99-106
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    • 2001
  • An overview of Silicon Carbide (SiC) Static Induction Transistor (SIT) development is presented. Basic conduction mechanisms are introduced and discussed, including ohmic, exponential, and space charge limited conduction (SCLC) mechanisms. Additionally, the impact of velocity saturation and temperature effects on SCLC are reviewed. The small-signal model, breakdown voltage, power density, and different gate structures are also discussed, before a final review of published SiC SIT results. Published S-band (3-4 GHz) results include 9.5 dB of gain and output power of 120 W, and L-band (1.3 GHz) results include 400 W output power, 7.7 dB of gain, and power density of 16.7 W/cm.

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Electrical Conduction in Y2O3-doped SrZrO3-metal Electrode System (Y2O3가 도핑된 SrZrO3-금속전극계의 전기전도 특성)

  • Baek, Hyun-Deok;Lee, Poong-Hun
    • Journal of the Korean Ceramic Society
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    • v.39 no.4
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    • pp.367-376
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    • 2002
  • Electrical conduction in $SrZr_{1-x}Y_xO_{3-\delta}$((x=0.05, 0.10)-metal electrode system was investigated by impedance spectroscopy and two-probe d.c. conductivity measurement. Electrode conductivity in anodic direction varies with $P_W^{1/2}$( and that in cathodic direction with $P_{O2}^{1/4}$ in oxidizing atmosphere. In hydrogen atmosphere, the addition of water vapor increased the electrode conductivity both in anodic and cathodic direction. Increasing dopant concentration from 5 to 10% showed a more than four times increase in anodic conduction as well as bulk conduction of the solid electrolyte. This observation implies that unfilled oxygen vacancy concentration increases rapidly as the dopant content increases in humid atmosphere. The activation energy of cathodic conduction in Pt and Ag electrode was nearly same below $800^{\circ}C$ which means the rate of cathodic reaction is determined by the reaction in the electrolyte surface rather than on the metal electrodes.