Modeling of divergent field experiments on layered polymer film

Abstract

This paper describes a rapid and robust axisymmetric hybrid algorithm to simulate divergent field experiments on layered polymer film. The hybrid algorithm uses a source distribution technique based on an axisymmetric boundary integral equation method (BIEM) to solve the Poisson equation and a 4 th order Runge-Kutta (RK4) method with an upwind scheme for time integration. Iterative stability is assured by satisfying the Courant-Friedrichs-Levy (CFL) stability criterion. The model computes dynamic temporal and spatial charge distributions assuming bipolar charge injection using Schottky emission and/or Fowler-Nordheim tunneling and field-dependent mobility while allowing for charge recombination and bulk and interfacial trapping/de-trapping. This model may be used to identify failure mechanisms such as charge packets, gaseous voids, and electroluminescence. Charge packets cause substantial increase of electric stress and could accelerate the breakdown of polymeric capacitors. Conditions for the creation of charge packets are identified and numerically demonstrated for a combination of impulsive step excitation, high charge injection, and discontinuous interface. Enhanced anisotropic interface conduction is shown to reduce charge accumulation, thus reducing E field contrast.