Be-induced island formation in CdSe/ZnSe heterostructures: Ensemble versussingle dot studies

We present photoluminescence (PL) studies on quantum islands formed below t he critical thickness for Stranski-Krastanow growth by a well-defined incor poration of Be nucleation centers in CdSe/ZnSe heterostructures. The occurr ence of spectrally narrow, individual photoluminescence peaks in spatially resolved PL spectra and a significant enhancement of the recombination life time clearly indicate the presence of zero-dimensional stales. A direct com parison of temperature-dependent single dot measurements with optical studi es on quantum dot (QD) ensembles demonstrates an efficient coupling between individual QD's at elevated temperatures.