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.