Optical absorption behaviour of metal/semiconductor hybrid nanoparticle composites

Semiconductor/metal hybrid nanoparticle composites have been prepared in a glass host by a modified melt/quench process and examined with respect to their optical properties. The coated hybrid nanoparticles exhibit surface plasmon resonance absorption spectra which are red-shifted compared with that of a dispersion of homogeneous Ag nanoparticles in the same host. The position of the plasmon resonance was a sensitive function of the heat treatment schedule. A theoretical model based on effective medium theory for the coated hybrid particles was used to describe the shift of the plasmon position in the optical spectra as a function of the coating thickness. The calculated absorption spectra of the coated hybrid particles agree well with the experimental results.