Recombination phenomenon in polyethylene under space charge dynamics and its effects on the external current evolution

This paper presents bipolar transport model results concerning the recombination phenomenon in a low-density polyethylene under direct current (dc) applied voltages. Results obtained indicate the existence of a threshold value of voltage between two different space charge dynamics. Indeed, we show that under low dc applied voltage, the total recombination rate density is dominated by the recombination between trapped electrons and trapped holes, while under high dc voltage, the recombination is governed by mobile electron-trapped hole and trapped electron-mobile hole recombinations. This is due to the fact that under low dc voltage, trapped charges dominate, while under high voltage, mobile charge density is much higher. In addition, we show the significant effect of the recombination phenomenon on the external current evolution at transient and steady states.