semiconductor device modeling based on continuity equation and Poisson's equation

Hi All,

I would like to get started on semiconductor device modeling. It will be based on drift-diffusion model in which the continuity equation and Poisson's equation are solved self-consistently. Does anyone have a have an example script (such as Matlab script) of doing this? It can be as simple as modeling the IV of a PN diode. It will greatly help me figure out the numerical details, such as the boundary condition, discretization etc. Thanks.