Luminescence of epitaxial sub-monolayer CdSe nanostructures in ZnSe

The photoluminescence of epitaxial CdSe/ZnSe nanostructures with nominal CdSe coverage equal to 0.15 monolayer (ML) and 0.58 ML was examined. Tightly localized quantum dot-like states occur in 0.58 ML nanostructures. Ultra-fine 0.15 ML heterostructures contain only weakly localized states with no distinct manifestation of strict quantum confinement. The increase of exciton concentration causes inelastic multi-particle scattering giving rise to a new emission line which is shifted spectrally by the value of light-heavy hole splitting in ZnSe host.