The Drift-Diffusion module can be used for the simulation of light emitting devices, bipolar transistors, MOS transistors, HEMTs and nanostructured devices. It is particularly suited for the study of strained III-V nanostructures due to the possibility to include the full strain tensor from realistic strain maps and quantization effects selfconsistently. The consistent treatment of inhomogeneous strain and polarization fields allows the simulation of piezoelectric devices.

The Drift-Diffusion module calculates transport of electrons and holes based on the Drift Diffusion approximation in 1, 2 and 3 dimensions. The continuity equations for electrons and holes are solved selfconsistently with the Poisson equation. The carrier densities are calculated assuming a local thermal equilibrium, using Boltzmann or Fermi-Dirac statistics. Mechanical, thermal and quantization effects can be included fully selfconsistently by coupling to the Elasticity, Thermal and Envelope Function Approximation modules.

Main characteristics of the model:

• Most common mobility and recombination models
• Single state bulk and surface trap models
• Inclusion of spontaneous and piezoelectric polarization
• Band parameters based on strain corrected k·p bulk model
• Selfconsistent coupling with Thermal and quantum mechanical modules
• Extensive material database