STEADY-STATE CONDUCTION IN LINEAR LOW-DENSITY POLYETHYLENE WITH POOLE-LOWERED TRAP DEPTH

A theory of steady-state conduction of injected space charge limited carriers 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 4.5xl019/cm3, yields good agreement with experimental current-field characteristics for fields up to 5xl05 V/cm in the temperature range 49 to 82.5°C. The final current I vs. 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/T2 vs. 1/T. The total activation energy is 0.83 eV at 2x10s V/cm, in agreement with other methods. © 1990 IEEE