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Electronic structure and chemical environment of Si nanoclusters embedded in a SiO2 matrix.

Anna Zimina 1S. Eisebitt 1Wolfgang Eberhardt 1Johannes Heitmann 2Margit Zacharias 2

1. Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung m. b. H. (BESSY), Albert-Einstein-Str, Berlin 12489, Germany
2. Max Planck Institute of Microstructure Physics (MPI), Weinberg 2, Halle 06120, Germany

Abstract

Using photon-in photon-out soft x-ray absorption and emission spectroscopy, the electronic structure of silicon nanoclusters embedded in an electrically insulating SiO2 host matrix is investigated as a function of nanocluster size. Using the new method of cluster preparation the size of the Si clusters is well controlled. The diameter of the nanoclusters was less than 5nm.

We find the nanoclusters to be of a core-shell structure with a crystalline Si core and a thin transition layer of a suboxide. Based on the spectroscopic data the electronic structure of the Si core and the chemical content of the suboxide shell are studied. The presented results are in agreement with photoluminescence measurements.

Effects of electronic quantum confinement are detected in the Si cores. We find that the influence of confined excitonic states and the presence of SiO2 matrix manifests itself predominantly in the unoccupied electronic states.

 

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Related papers

Presentation: Oral at E-MRS Fall Meeting 2006, Symposium A, by Anna Zimina
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-12 07:55
Revised:   2009-06-07 00:44