Non-Ohmic conduction in polydiacetylene thin films

Abstract We have studied the current–voltage ( I – V ) characteristics of polydiacetylene (PDA) thin films in the temperature region 300–1.7 K. It was found that at electric fields higher than 2 × 10 4 V/cm, the I – V characteristics are strongly super-linear with negative temperature coefficient of starting voltage. Negative gate voltage increases the source-drain current (the effect is more pronounced at low temperature), whereas the magnetic field up to 7 T does not affect it. The results demonstrate that at low temperature the charge transport is mainly supported due to a charge injection and tunneling from the metallic banks, whereas at higher temperatures the activation energy is related to the band gap mismatch between the different polymer chains or granules.