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    • Keywords


      Porphyrazine; a.c. conductivity; correlated barrier hopping; spin coating; tunnelling.

    • Abstract


      The d.c. and a.c. electrical transport properties of Au/Pz/Au devices with various thickness of Pz(octakis[(4-tert-butylbenzylthio)-porphyrazinato]Cu(II)) layer have been investigated. Measurements revealed that, in contrast to previously investigated Au/Pc/Au structures, low voltage d.c. behaviour of the films can be described by the field-lowering mechanisms with a $\log$(𝐽) ∝ 𝑉1/2 current density-voltage characteristics under forward and reverse bias. For high reverse voltages, the observed ln (𝐽/𝑉2) - 1/𝑉 characteristics indicated that the origin of conduction mechanism is Fowler–Nordheim tunnelling (FNT). On the other hand, the voltage dependence of current density at the higher forward-voltage region indicates that the mechanism of conduction in Au/Pz/Au devices is space charge limited conduction dominated by exponential trap distribution. A thickness independent barrier height was observed for tunnelling, while the total trap concentration show a general tendency to decrease with increasing film thickness. The a.c. conductivity showed two regions in the ln (𝜎a.c.) - ln(𝑓) plots having different slopes, leading to the conclusion that for low frequency region, the dominant conduction mechanism is a small polaron tunnelling at all temperatures, whereas for high frequency region, correlated barrier hopping model is the dominant mechanism in the investigated devices.

    • Author Affiliations


      Bahadir Keskin1 Ahmet Altindal2 Ulvi Avciata2 Ahmet Gül3

      1. Department of Chemistry, Yildiz Technical University, 34210 Istanbul, Turkey
      2. Department of Physics, Yildiz Technical University, 34210 Istanbul, Turkey
      3. Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey
    • Dates

  • Bulletin of Materials Science | News

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