Relative contributions of bulk and interface effects to the AC conductivity in evaporated silicon-monoxide films sandwiched between gold electrodes

Abstract

AC conductivity of Au-SiO-Au structures has been investigated between 10^-1 to 10⁵ Hz and 77 to 423K. Low frequency measurements confirm, for a large class of specimens, the results obtained previously by Bigorgne et al. (1974); namely the existence of Schottky barriers at the interfaces. The behaviour of the specimens agrees with a model established by Simmons, Nadkarni and Lancaster (1970). Hopping phenomena also occur and become predominant at a relatively high frequency or low temperature. An equivalent circuit derived from the Simmons, Nadkarni and Lancaster model, is proposed; it takes into account the two behaviours which coexist in the entire investigated temperature and frequency ranges. It has been found that activation energies corresponding to AC and DC conductivities are about the same.