Multiple states in surface lattice constant behavior during the molecular beam epitaxial growth of ZnTe-ZnS strained layer superlattices

ZnTe-ZnS short period (∼30 Å) strained layer superlattices were grown by molecular beam epitaxy and the growth process was observed in situ by using reflection high energy electron diffraction (RHEED). Surface lattice constant (a_∥) behavior shows a transition from one state in which a_∥ is equal to that of the substrate to the other in which a_∥ depends on the depositing constituents. RHEED patterns show the same streaks for both states except the difference in streak separation. Transmission electron micrograph reveals that the resultant multilayer structures of the two states have the same quality. The experimental data may suggest a possible assumption that there exists multiple states for two-dimensional growth of a strained system with substantial lattice mismatch.