Carrier mobility in ethylene-vinylacetate copolymer estimated by transient space charge

Carrier mobility in an ethylene vinyl acetate (EVA) copolymer film was measured by a new technique. The time-dependent charge distribution was monitored by the pulsed-electroacoustic method when a pulse voltage was superposed on a dc bias voltage. A positive charge packet was injected from the anode soon after the pulse application, and moved towards the cathode. It was suggested from the movement of the charge packet that the mobility of the positive carrier at 10 to 60 MV/m was in the order of 10(-13) m(2)/Vs at room temperature. When the pulse voltage was very high, a charge packet appeared within the bulk, suggesting that carrier dissociation takes place.