Comparison of models for Raman spectra of Si nanocrystals

Within the framework of a partial-density approach, the confinement of vibrations in spherical Si nanocrystals is studied and the Raman frequency shifts of Si spheres with different sizes are derived based on the Raman spectra obtained by a bond-polarizability model. The results obtained by the bond-polarizability model are compared with those by the phenomenological model developed by Richter et al. [Solid State Commun. 39, 625 (1981)].