Models of electron trapping and transport in polyethylene: Current--voltage characteristics

We present a unified method to estimate current–voltage characteristics of insulators starting from

ab initio electronic calculations of the properties of the dielectric material. The method consists of

three stages: 1) computation of trap energy distributions for excess electrons by means of density

functional theory, 2) computation of local electron mobilities from a multiple trapping electron

transport model which includes trap filling effects and 3) macroscopic integration of the Poisson

and current–field equations, using local electron mobility data from stage 2) to predict the current–

voltage characteristics for a material of a given width. The only input to this procedure is the

chemical composition of the insulating material. We compare our model results with experimental

studies of the current–voltage curve of cross-linked polyethylene.