Temperature Dependence of DC Electrical Conduction in Plasma Polymerized Pyrrole Thin Films

M. M. Kamal and A. H. Bhuiyan

The temperature dependence of direct current (DC) electrical conduction in plasma polymerized pyrrole (PPPy) thin films has been discussed in this article. A parallel plate capacitively coupled glow discharge reactor was employed to deposit PPPy thin films and different properties of the films were studied in detail. In the study of DC conduction properties, the current density-voltage (J-V) characteristics of PPPy thin films at room temperature indicated that in the low field region the conduction obeys Ohm’s law but at high field non-linear characteristics were observed. The J-V characteristics at different temperatures showed that the current density in both the voltage regions is increased slightly with increasing temperature which indicated the temperature dependence of the conductivity. From the Arrhenius plots activation energies were calculated in both the low and high temperature region. It is observed that activation energy is decreased with the decrease of temperature which was an indication of a gradual transition to the hopping regime. The change in activation energy at higher temperature in comparison to that at lower temperature has been attributed to a considerable temperature-dependence of SCLC mechanism.