ZnTeZnS strained-layer superlattices grown by ALE and MBE: Effects of strain on ZnTe incorporation

The ZnTe incorporation rate was found to be less than intended when it was grown by atomic layer epitaxy (ALE) as a constituent layer of a ZnTe-ZnS strained-layer superlattice (SLS). The actual layer thickness of ZnTe decreased almost linearly with increase in strain caused by lattice mismatching for a constant growth temperature. This linear relation is the same for the SLSs grown directly on GaAs(100) and on the ZnSe buffer layer, but a ZnTe buffer lessens the degree of decrease in ZnTe incorporation. The compressive stress might enhance re-evaporation of adatoms. Raman spectra of the SLSs show that LO phonon lines of ZnS shift toward lower energy with increasing tensile stress on the ZnS layer. ZnTe LO phonon lines show no systematic shift, indicating lattice relaxation.