Space charge behavior in LDPE with evaporated electrode under ultra-high electric field

We had reported a large amount of positive packet-like charge injection from the anode electrode into low-density polyethylene when the dc ultra-high stress was applied thorough the electrode of semiconducting layer by using the pulsed electroacoustic (PEA) system. In the report, it was thought that the packet-like charge was strongly affected to the breakdown phenomena. Since it has been known that the charge injection was also strongly affected by the material of the electrode, the dependence of the charge injection on electrode materials was investigated by using Au and Bi (bismuth) evaporated electrodes. From the result, the injection of the large amount of positive packet-like charge was observed in all cases. However, the amount and the injected depth of the positive packet-like charge were restricted by the evaporated electrode.