Tight-binding calculations of the subband structures of zincblende-semiconductor [001] quantum wells

The scattering-theoretic T-matrix method is used to calculate the subband structures of GaAs−ZnSe and ZnSe−ZnS_xSe_1−x [001] quantum wells within an empirical tight-binding model, that includes the bulk Г₆, Г₇ and Г₈ valence- and conduction bands. The resulting confinement energies for vanishing lateral crystal momentumk _‖ are compared with those, that are obtained from a simple effective mass model and effects are found and predicted which the effective mass model cannot account for. The effect of the band nonparabolicity and the influence of the microscopic sequence of atomic layers, which determines the symmetry properties of a quantum well, are studied for the GaAs−ZnSe wells.