Space charge behaviors near the interface between different low-density polyethylenes

We investigated the space charge behaviors near the interface between different low-density polyethylenes (LDPE) by using the PEA method. Charge carriers were mainly injected from the semicon electrode in a specimen of Al/LDPE/LDPE/LDPE/semicon and they moved through the interface to the counter Al electrode. Charge carriers moving from LDPE of a lower density to LDPE of a higher one were accumulated near the interface to form space charge, while there was no space charge accumulation for carriers moving in the opposite direction. It suggests that charge carriers are more mobile in LDPE of a lower density. The mobilities of charge carriers were also estimated from the change in space charge profile with time and positive carriers were more mobile in LDPE than negative ones. These space charge behaviors were discussed compared with the results of DC conduction