Phase Separation in Cd sub (1-x) Zn sub x Te Grown by Molecular Beam Epitaxy.

The ternary system Cd sub (1-x) Zn sub x Te has been a leading candidate for use as a lattice matched buffer layer for a variety of Hg-containing II-VI compounds. We have grown films over the entire composition range on GaAs substrates. We find that both ZnTe and CdTe grow well, but that the films degrade substantially for ternary compositions. Synchrotron x-ray scattering shows that the ternary films are phase separated, with CdTe, ZnTe, and differing compositions of Cd sub (1-x) Zn sub x Te all present within one film. Transmission electron microscope images show features which are similar to those seen in In sub (1- x) Ga sub x As sub (1-y) P sub y which has undergone a partial spinodal decomposition.