Numerical modelling of equilibrium charge separation in poled devices

We describe an efficient numerical procedure for the equilibrium solution of the internal electric field distribution resulting from poling of photo-refractive materials. This technique has been developed to model the equilibrium state in poled bulk devices requiring bulk charge neutrality to facilitate the modelling of blocking boundaries for a high externally applied voltage (bias) in the k-V range for a small number of points. This technique is an improvement on existing conventional numerical techniques employed for modelling semiconductor devices that are intended for low bias. This method can also accommodate the modelling of planar insulators and organic optical materials. We develop an algorithm incorporating the existing Newton-Raphson method for solving Kukhtarev's equations that enforces conservation of charge within the modelled system. We apply this technique to model one-dimensional charge separation in ultraviolet (UV) excited poling of glass and, report numerical equilibrium electric field distribution for a 2 kV bias. The convergence behaviour of the algorithm is investigated and compared against the Newton-Raphson method.