EXAFS 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 MBE. This data 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 discuss accommodation of this increased strain through bond bending and bond stretching. We also discuss other experiments in progress to more fully understand these interfaces.