Steady-state conduction in linear low-density polyethylene with Poole-lowered trap depth

Abstract

A theory of steady-state conduction of space-charge-limited carriers injected into linear low-density polyethylene with Poole-lowered trap depth is presented. Injected carriers are deeply trapped at crystalline-amorphous boundaries before the steady state is reached. At elevated temperatures, they are thermally excited to the conduction band in the crystalline regions, and then hop with field-independent mobility through the shallow band-tail states of the amorphous regions. A deep-trap-site separation of 2.8 nm, corresponding to 4.5*10/sup 19//cm/sup 3/, yields good agreement with experimental current-field characteristics for fields up to 5*10/sup 5/ V/cm in the temperature range 49 to 82.5 degrees C. The final equation for current I versus field F and temperature T equation shows that the activation energy of the detrapping and transport processes are additive on a semilog plot of I/T/sup 2/ versus 1/T. The total activation energy is 0.83 eV at 2*10/sup 5/ V/cm, in agreement with the results of other methods. >