Asymptotic of the Solutions of the Initial Boundary Value Problem for the Diffusion Equations for Semiconductors (Ⅱ)

The paper deal with the asymptotic behavior of the solutions to the initial boundary value problem for unipolar drift diffusion equations for semiconductors. Under the proper assumptions on doping profile and initial value, we prove that the smooth solutions to these evolutionary problems tend to the unique stationary solution exponentially as time tends to infinity.