Nanoparticle layers of CdSe buried in oxide and chalcogenide thin film matrices

Nanoparticles of CdSe embedded in amorphous SiOx GeS2 and polycrystalline ZnSe thin films have been produced by sequential physical vapour deposition of CdSe and one of the matrix materials. High-resolution electron microscopy has been used to prove the formation of CdSe nanoparticles. Particles with nearly spherical shape were observed whose spatial distribution follows the surface morphology of the 'matrix' films. The mechanism of nanoparticle formation on a rough surface has been discussed. It has been found that annealing of SiOx-CdSe films at 973 K leads to the formation of isolated CdSe nanoparticles homogeneously distributed in the matrix. Quantum-size increase in the optical band gap of CdSe nanoparticles has been observed in all matrices used. (C) 2002 Elsevier Science Ltd. All rights reserved.