On the Nature of High Field Charge Transport in Reinforced Silicone Dielectrics: Experiment and Simulation

TL;DR

This study investigates high field charge transport in reinforced silicone dielectrics through experiments and Monte Carlo simulations, revealing the importance of localized states, trapping, and heterogeneity in charge mobility.

Contribution

It combines experimental measurements with Monte Carlo simulations to elucidate charge transport mechanisms in reinforced silicone dielectrics, highlighting the role of localized states and trapping.

Findings

Charge injection likely dominated by tunneling to localized states

Transient transport caused by charge relaxation into deep traps

Charge mobility is highly heterogeneous due to trap distribution

Abstract

The high field charge injection and transport properties in reinforced silicone dielectrics were investigated by measuring the time-dependent space charge distribution and the current under dc conditions up to the breakdown field, and were compared with properties of other dielectric polymers. It is argued that the energy and spatial distribution of localized electronic states are crucial to determining these properties for polymer dielectrics. Tunneling to localized states likely dominates the charge injection process. A transient transport regime arises due to the relaxation of charge carriers into deep traps at the energy band tails, and is successfully verified by a Monte Carlo simulation using the multiple-hopping model. The charge carrier mobility is found to be highly heterogeneous due to non-uniform trapping. The slow moving electron packet exhibits a negative field dependent drift velocity possibly due to the spatial disorder of traps.