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Charge Limited Currents (charge + limited_current)

Distribution by Scientific Domains
Physics and Astronomy100%

Kinds of Charge Limited Currents

  • space charge limited current
    		•

    Selected Abstracts

    Ionic and electronic defects in a-BaTiO3 thin films studied by transient and steady state conductivity measurements

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2007
    F. El Kamel
    Abstract Conduction mechanisms in BaTiO3 films deposited at low temperatures on Cu-electrodes have been investigated in transient and steady regimes as a function of temperatures and electric field. This work aims to identify possible defects which govern the leakage current. Electrical measurements reveal that Space Charge Limited Current (SCLC) constitutes the main leakage mechanism in both the transient and the steady regimes. Based on the theory of SCLC, two types of defects can be detected. At higher temperatures, oxygen vacancies constitute the main defects which migrate across the film to generate an ionic leakage current. Diffusion of these defects is thermally activated with an activation energy around 1 eV. Moreover, at lower temperatures the J - E measurements reveals the presence of a discrete set of shallow traps at 0.45 eV below the conduction band with an effective density of 4 × 1022 m,3. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Measuring carrier mobility in conventional multilayer organic light emitting devices by delayed exciton generation

    PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2008
    S. Reineke
    Abstract The authors present an alternative method for the determination of the charge carrier mobility of organic thin films. In contrast to known methods like space charge limited current, field effect transistor and time of flight approaches, we determine the charge carrier mobility of a mixed film, serving as emission layer, within the conventional multilayer device architecture. We make use of a strong delayed generation feature in the electroluminescent decay, following a short voltage pump pulse in a time-resolved set-up. Taking into account the preferentially electron transporting properties of the film, the mobility of a N,N ,-di(naphthalen-2-yl)- N,N ,-diphenyl-benzidine (NPB):tris(1-phenylisoquinoline) iridium [Ir(piq)3] mixed film is found to be on the order of 10,5 cm2 (Vs),1. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Effect of substrate temperature on the properties of vacuum evaporated indium selenide thin films

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 7 2005
    C. Viswanathan
    Abstract Thin films of InSe were obtained by thermal evaporation techniques on glass substrates maintained at various temperatures (Tsb = 30°, 400°C). X-ray diffraction analysis showed the occurrence of amorphous to polycrystalline transformation in the films deposited at higher substrate temperature (400°C). The polycrystalline films were found to have a hexagonal lattice. Compositions of these films have been characterized by EDAX and the surface analysis by scanning electron microscopy. Optical properties of the films, investigated by using spectrophotometer transmittance spectra in the wavelength range (300 , 1100 nm), were explained in terms of substrate temperatures. Films formed at room temperature showed an optical band gap (Egopt) 1.56 eV; where as the films formed at 400°C were found to have a Egopt of 1.92 eV. The increase in the value of Egopt with Tsb treatment is interpreted in terms of the density of states model as proposed by Mott and Davis. The analysis of current -Voltage characteristics, based on space charge limited currents (SCLC) measurements, confirms the exponential decrease of density of states from the conduction band edge towards the Fermi level for both the amorphous and polycrystalline films. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Current filamentation and negative differential resistance in C60 diodes

    PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2008
    Philipp Stadler
    Abstract Current-Voltage (IV) measurements of C60 thin film diodes in the temperature range of 300,4.2 K are presented. The fullerene diodes exhibit space charge limited currents as well as reversible voltage instabilities (S-shape IV characteristics) at temperatures below 200 K and at high current densities. The instabilities are similar to certain charge transport effects in amorphous inorganic semiconductors, which are explained by injection of holes and electrons at the same time and charge trapping near the electrodes. Beyond certain current densities conductive filaments in the fullerene bulk phase are formed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]