Abstract
A tight-binding models which account for band mixing, strain and external applied potentials in a self-consistent fashion has been developed. This allows us to describe electronic and optical properties of nanostructured devices beyond the usual envelope function approximation. This model can be applied to direct and indirect gap semiconductors thus allowing for instance the self-consistent calculation of band profile and carrier control in pseudomorphic InGaAs/GaAs HEMTs and SiGe/Si MODFETs.