Simulation of space charge in polyethylene naphthalate: Effect of charge carrier mobility

The aim of this work is to study, with a numerical simulation, the space charge dynamics in polymers, where a particular intent is accorded to the mobility parameter. Analysis of experimental transient charging current, with anomalous peak, under dc field, in polyethylene naphthalate, show that carriers mobility depends strongly on the temperature and weakly on applied field (probably due to its small range variation). The temperature dependence of the mobility follows an Arrhenius-like law, with apparent activation energy of 0.45 eV. From these experimental results, a model of space charge was considered, assuming Schottky injection at electrodes. Transient space-charge distributions, internal field profile and external charging current, were numerically simulated based on this model. It was shown that the space-charge dynamics depends upon the mobility of carriers.