  Existence of intrinsic carrier interface states in heterostructures with no
common atom at the interface (such as ZnSe/BeTe) is evidenced experimentally by
ellipsometry and photoluminescence spectroscopy. These states are located on
interfaces and lie inside the effective band gap of the structure; they are
characterized by a high density and high carrier capture rate. A tight binding
model confirms theoretically the existence of these states in ZnSe/BeTe
heterostructures for a ZnTe-type interface, in contrast to the case of the
BeSe-type interface for which they do not exist.
