  We present a combined experimental and theoretical approach for the
determination of the low-temperature valence band offset (VBO) at CdSe/ZnTe
heterojunctions with underlying zincblende crystal structure. On the
experimental side, the optical transition of the type II interface allows for a
precise measurement of the type II band gap. We show how the excitation-power
dependent shift of this photoluminescence (PL) signal can be used for any type
II system for a precise determination of the VBO. On the theoretical side, we
use a refined empirical tight-binding parametrization in order to accurately
reproduce the band structure and density of states around the band gap region
of cubic CdSe and ZnTe and then calculate the branch point energy (also known
as charge neutrality level) for both materials. Because of the cubic crystal
structure and the small lattice mismatch across the interface, the VBO for the
material system under consideration can then be obtained from a charge
neutrality condition, in good agreement with the PL measurements.
