3D VERSUS 1D QUANTUM CONFINEMENT IN COHERENTLY STRAINED CDS ZNS QUANTUM STRUCTURES/

Monolayer fluctuations in ultrathin, coherently strained CdS/ZnS quant um structures result in a very strong localization of excitons. The de epest localized excitons can be considered as individual, decoupled an d three-dimensionally confined. Consequently, fingerprints of zero-dim ensionality are found in the optical spectra like single, ultranarrow luminescence lines in micro-photoluminescence and spectrally broad opt ical gain in the deep blue spectral range. The exchange splitting is p roven and a strong enhancement over the bulk value is observed.