Electrical conductivity of the polycrystalline films of p-quaterphenyl

Some results of p-quaterphenyl thin films studies are presented. The mechanism of DC conductivity within unordered polycrystalline structures of p-quaterphenyl was investigated. The measurements were carried out for p-quaterphenyl films with thicknesses varying from 1 to 10 mu m. During the experiment the polarization voltage and the temperature were changed from 0 to 120 V and 16 to 325 K, respectively. Gold and aluminium were used as materials for the electrodes. The obtained results and their analysis indicate that the injection of charge carriers from the electrodes into the area of the investigated material proceeds by field- and thermoemission. The charge transport through the material's bulk is controlled by traps, i.e., a hopping mechanism and the Poole-Frenkel phenomenon. The determined values of the activation energy are in the range from kT to 0.1 eV. (C) 2000 Elsevier Science S.A. All rights reserved.