AC conduction of evaporated silicon-monoxide films

Abstract

AC conductivity of evaporated silicon-monoxide films sandwiched between gold electrodes has been investigated in the frequency range 0.1 to 105 Hz and in the temperature range 173 to 415K For most of the specimens studied it is shown that, for high frequencies, the AC conductivity is proportional to omega n, omega being the circular frequency and n a temperature-dependent quantity; the value of n decreases linearly from 0.82 to 0.48 when the temperature increases from 173 to 415K. It is emphasised that these experimental results cannot be analysed in terms of a quantum hopping conduction mechanism proposed by Pollak and Geballe, but they seem in agreement with a theory derived by Pike. In this theory, the hopping of electrons between two localised sites over the separating barrier is considered; the height of the barrier is lowered by the overlapping of the Coulomb-like potentials. The activation energy of the localised states deduced from the Pike model agrees with the value of the DC activation energy.