Space charge behavior of polyimide film

Abstract

Space charge distributions in polyimide films strongly depend upon electric field, temperature, water content and so on. When a low dc field was applied, positive and negative homo space charges were observed near the respective electrodes. When the applied field was higher than 30 MV/m, additional positive and negative hetero space charges were also observed. The amounts of these charges depended upon applied field. The temperature dependence of the amounts of homo space charge showed a thermally-activated process. After drying by the heat treatment, the homo space charges were much reduced at 296 K and at 333 K. This suggests that the charge injections from the electrodes are strongly affected by absorbed water. The hetero space charges were not affected by drying. After short-circuiting, the homo space charges quickly decreased but the hetero space charges were very stable.