Extended x-ray-absorption fine-structure studies of interfaces in ZnTe/CdSe superlattices

Polarization-dependent grazing incidence EXAFS, employing the electron yield technique, has been used to study the local atomic structure of two different short-period ZnTe/CdSe(001) superlattices grown by molecular-beam epitaxy. The data obtained for the Se edge at room temperature indicate Zn-Se and Cd-Te coordination numbers greater than those expected for sharp interfaces in the superlattice. Although strain would appear to suppress interdiffusion, we show that the results are consistent with an interchange of Zn and Cd atoms across the Zn-Se interface, and Se and Te atoms across the Cd-Te interface. We also discuss accommodation of this increased strain through bond bending and bond stretching.