CALCULATION OF HYDROSTATIC AND UNIAXIAL DEFORMATION POTENTIALS WITH A SELF-CONSISTENT TIGHT-BINDING MODEL FOR ZN-CATION-BASED II-VI-COMPOUNDS

A self-consistent tight-binding (SCTB) calculation of the deformation potentials is performed for ZnTe, ZnSe, and ZnS. Tight-binding bulk parameters reproducing photoemission and reflectivity experiments are given for these compounds. Then the strain effects are considered in the SCTB model, which allows the calculation of the hydrostatic deformation potential and of the nonlinear variation of the fundamental E0 gap with the relative change in the lattice constant DELTA-a/a0. The method is applied to the determination of the offset in the strained ZnS-ZnSe system. Results are in good agreement with experimental and other theoretical works.