Electrical conductivity of the polycrystalline films of p-quaterphenyl

Some results of p-quaterphenyl thin films studies are presented. The mechan ism of DC conductivity within unordered polycrystalline structures of p-qua terphenyl was investigated. The measurements were carried out for p-quaterp henyl films with thicknesses varying from 1 to 10 mu m. During the experime nt 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 t he injection of charge carriers from the electrodes into the area of the in vestigated material proceeds by field- and thermoemission. The charge trans port through the material's bulk is controlled by traps, i.e., a hopping me chanism and the Poole-Frenkel phenomenon. The determined values of the acti vation energy are in the range from kT to 0.1 eV. (C) 2000 Elsevier Science S.A. All rights reserved.