[en] In the framework of this thesis shell-like constructed nano-heterostructures oc CdTe, CdS, and CdSe were fabricated and examined especially in view of their optical properties. A new variant of the CdTe nanocrystal synthesis in ODE as a highly-boiling, non-coordinating solvent was developed. These CdTe nanocrystals were coated both with CdS and with CdSe. Thereby for both kinds of the coatings different methods were tested, and each a synthesis method could be found, which yields core-shell nanocrystals with low polydispersity and good optical properties (narrow emission signals and high quantum yields). Furthermore core-shell-shell nanocrystals of CdTe/CdS/CdSe were synthesized. The optical properties (first electronic transition) of the fabricated core-shell and core-shell-shell particles were compared with theoretical calculations in the framework of the effective-mass approximation. This comparison resulted for the particles coated with CdSe a well, for the particles coated with CdS however only a moderate agreement. Also the transmission-electron-microscopical images suggest that especially the coating with CdS slopes non quantitatively concerning the applied precursor quantity. The emission lifetimes of the different systems show however, that the charge-carrier separation in the excited state of the CdTe/CdS/CdSe core-shell-shell nanocrystals theoretically to be expected really occurs. By introduction of the CdS layer an elongation of the emission lifetime of the nanocrystals could be reached. Especially it was shown that it is possible to fabricate different nanostructures, the emission lifetimes of which are different, although they emitt light at the same wavelength