Carrier mobility in insulating polymer influenced by hysteresis of applied voltage

Carrier mobility is one of the most important parameters to characterize dielectrics. The mobility, however, may have a hysteresis when subjected to a high field. Indeed it is reported that a polymeric film specimen that has been subjected to a high field is more conductive than the virgin specimen, suggesting the rise in mobility. Therefore, we tried a direct measurement of mobility in ethylene vinyl acetate copolymer (EVA) film, using the pulsed electroacoustic method. It was observed that the carrier mobility after the high field application was greater than that before the application. It is considered that dissociated carrier which has been generated under the high field lead to a faster mobility in the film.