Charge injection/ejection and trapping in low-density polyethylene at low and medium fields

Very long time dc measurements have been carried out to analyze charge injection/ejection and trapping in low-density polyethylene. The basic idea was to compare the total charge involved in the charging step and the total charge stored in the material. The equality of the two charges demonstrates that the charge carriers do not pass through the sample. The injected electrons are trapped very close to the cathode to form a negative layer. It is suggested that near the anode the field ionizes the impurity atoms and/or the neutral molecules associated with structural defects to produce positive ions.