Electronic structure and chemical environment of silicon nanoclusters embedded in a silicon dioxide matrix

Using photon-in photon-out soft x-ray spectroscopy, the electronic structure of silicon nanoclusters embedded in an electrically insulating SiO2 host matrix is investigated as a function of nanocluster size. We find the nanoclusters to be of a core-shell structure with a crystalline Si core and a thin transition layer of a suboxide. Effects of electronic quantum confinement are detected in the Si cores. We find that the influence of confined excitonic states manifests itself predominantly in the unoccupied electronic states. (c) 2006 American Institute of Physics.