Space charge behavior of LDPE with a blocking electrode

In this paper, to better understand the space charge behavior of LDPE, we tried to distinguish various processes resulting in space charge. A polyethylene terephthalate (PET) thin film (about 2.5 μm) was set between LDPE (about 100 μm) and semiconductive electrode to block carriers. Then, carriers injected from the electrode and those generated in the bulk can be separated. The space charge profiles in LDPE with a blocking electrode indicated that carriers generated in the bulk and injected from the aluminum cathode made little contribution to space charge in the specimen. Carriers injected from the semiconductive anode played an important role in space charge formation. No space charge was observed in a 100 μm PET film under a DC field of 50 MVm^-1 and PET film showed less DC current than LDPE. These suggest that a PET thin film is suitable to make a blocking electrode.