In this work, the excitonic properties of ZnSe/ZnSxSe1-x strained superlattices (SLs) and quantum wells (QWs) are studied taking into account spin-orbit splitting, strain, and interfacial effects. The broadening of excitonic related photoluminescence (PL) spectra due to the existence of gradual interfaces with thickness of 10 Angstrom is shown to be of the order of 30 meV for a 30 Angstrom ZnSe/ZnS0.18Se0.82 QW. (C) 2004 Elsevier B.V. All rights reserved.