QUANTUM-WELLS WITHIN QUANTUM DOTS, A CDS HGS NANOHETEROSTRUCTURE WITHGLOBAL AND LOCAL CONFINEMENT/

Semiconductor nanocrystals prepared by methods of wet chemistry are si milar to MBE grown quantum dots where the mobility of the charge carri ers is reduced to zero dimensionality. In this paper we summarize the physics of a unique system in which the charge carriers are locally co nfined within a heterogeneous quantum dot. With high resolution electr on microscopy we will show that epitaxial growth ot atomic layer preci sion is possible by methods of solution chemistry leading to CdS quant um dots with embedded HgS quantum wells (QDQWs). The photophysics of t his' system is investigated by time-correlated single photon counting, transient differential absorption and fluorescence line narrowing spe ctroscopies. The results reflect the very complex electronic structure of this new kind of matter which can be explained by an extended effe ctive mass approach.