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(Color online) Series of SXE spectra as a function of incident photon energy recorded for the sample with an initial SiO layer of thickness. The intense elastic peaks are clipped for clarity. For excitation energy the SXE spectrum for a bulk Si has been added for comparison (dashed line). The inset displays schematically how the as grown multilayer structure (top) is converted into Si nanoclusters embedded in a matrix upon annealing (bottom), as described in detail in Ref. 5. The contribution to the total emission spectrum is listed on the right.
(Color online) (a) SXE spectra excited at and (b) PFY-SXA spectra are presented as a function of nanocluster size: (red), (blue), (orange), and (green) are the initial thicknesses of the SiO layer. A spectrum of bulk crystalline Si (black) has been superimposed for comparison. Vertical lines mark the VB and CB edges of the bulk crystalline Si. Elastic peaks in SXE spectra are clipped for clarity.
Size dependent compositional and geometric parameters of the silicon naoncrystals as determined from the SXE spectra.
Comparison of the experimental shift of the absorption edge (a) with the theoretical calculations: quantum confinement prediction in effective mass approximation assuming infinite barriers and no excitonic contribution (b); exciton contribution, without (Ref. 21) (c) and with (Ref. 22) (d) size dependent dielectric constant within the nanocrystal; exciton contribution including the image contribution to the exciton binding energy and (e) (Ref. 25). The excitonic contributions have to be subtracted from column (b) for comparison with the experimental result in (a). All energies are in eV.
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