Electrical conduction mechanisms in thermally evaporated lead phthalocyanine thin films

The AC electrical behaviour of sandwich devices fabricated entirely in vacuum using thermally evaporated thin films of lead phthalocyanine and gold electrodes is observed over the frequency range 10(4) to 4 x 10(6) Hz and the temperature range 160 to 440 K. In the high-frequency region the AC conductivity is proportional to omega(s). Capacitance and dissipation factors decrease with increasing frequency and increase with increasing temperature. The results obtained show the relative importance of the hopping model and band theory in describing the film conduction with regard to the operating conditions. The former is dominant at low temperatures and high frequencies, whereas the latter is dominant at high temperatures and low frequencies.