Subband Diffusion Models for Quantum Transport in a Strong Force Regime

We derive semi classical approximations to quantum transport models in thin slabs with applications to SOI (Silicon Oxide on Insulator) type semiconductor devices via a sub band approach. In the regime considered the forces acting on the particles across the slab are much larger than the forces in the lateral direction of the slab. In a semi classical limit the transport picture can be described on large time scales by a system of sub band convection diffusion equations with an inter band collision operator, modeling the transfer of mass (charge) between the different eigenspaces and driving the system towards a local Maxwellian equilibrium.