The Relationships between the Crystalline Structure and Trap Properties of Annealed Poly（Ethylene Terephthalate） Electrets

A series of poly（ethylene terephthalate） （PET） films with different crystallinity are obtained by annealing at 110°C in various time intervals. The trap properties of crystallized PET electrets are studied by method of thermally stimulated current（TSC）. It is found that the mean depth of trap level increases with increasing crystallinity.Crystallization by annealing makes the depth of trap level deep, but the ability to trap charge carriers shows a maximum at crystallinity of 20%.