Spectroscopic Studies Of CdSe/ZnSe Core/shell Nanoparticles

Electronic and chemical passivation of CdSe nanocrystals has been achieved by growth of a thin ZnSe layer in aqueous solution. Small aliquots (0.1 ml) of shell precursors have been alternatively added to the CdSe cores, and the growth of ZnSe shell is characterized by absorption, photoluminescence and photoluminescence excitation spectroscopic measurements. X-ray scattering has been applied to know the crystallinity of the nanostructures. The CdSe shows wurtzite crystal structure with traces of zinc blende, but zinc blende structure dominates after ZnSe growth. Photoluminescence excitation spectrum of the samples at room temperature has been exploited to study the electronic transitions of nanocrystalline CdSe prior to growth of ZnSe shell and after.