High field conduction of the composites of low-density polyethylene/nano SiOx and low-density polyethylene/micrometer SiO2

High field conduction of both types of composite of low-density polyethylene (LDPE)/nano SiO_x and LDPE/micrometer SiO₂ was studied at various temperatures in detail, as well as the effect of the contents of both filler (nano SiO_x and micrometer SiO₂) on high field conduction. Schottky effect, Poole-Frenkel effect, space-charge-limited conduction (SCLC), Schottky effect, Frenkel effect and ion hopping conduction were used to fit our results. It is pointed out that both Schottky effect and Poole-Frenkel effect do not fit well for all of the high field conduction. However, to some extent, both ion hopping conduction and space charge limited conduction fits the results. The relationship between trap level and its related density was investigated with isothermal current decay. It is shown that traps introducing by the nano SiO_x and micrometer SiO₂ modulate the high field conduction of both composites.