Abstract
A modified local density approximation which takes into account that the wave functions are zero at the semiconductor‐insulator interface is used to investigate the influence of this behaviour of the wave function on the mobility. The result follows from a generalization of the classical transport description. It is shown that the decrease of the mobility due to surface scattering is reduced by the influence of the wave functions. In addition a modification of the expression for the diffusion current connected with the influence of the wave functions is given.