Modified Raman confinement model for Si nanocrystals

A modified one-phonon confinement model is developed for the calculation of micro-Raman spectra in Si nanocrystals, permitting the simultaneous determination of the Raman frequency, intensity, and linewidth. Using a specific spatial correlation function and the Si phonon dispersion relations, the Raman spectra are calculated under the limitations imposed on the wave vector by the spatial confinement. Results are obtained as a function of the Si nanocrystal size in the range 1.2-100 nm. The frequency shift and line broadening of the Raman spectra are compared with experimental results reported in the literature.