Islands at semiconductor interfaces

Within the effective-mass, one-band approximation we have performed model computations aiming at the description of roughness at semiconductor heterointerfaces, with a characteristic height scale of 2 monolayers (1 ML=0.283 nm) and a lateral extension going from a few to ∼100 Å. Actual calculations are done on GaAs/AlAs quantum well structures, which are the most studied and well-characterized ones. It is shown that this sort of defect at the interface strongly affects the electronic properties of the system, in terms of eigenvalues and charge localization.