Band gap tuning in Si-SiO2 nanocomposite: Interplay of confinement effect and surface/interface bonding.

Correlation between size, bonding of Si and O at the surface/interface of Si nanocrystals and frequency of Si phonons in Si-SiO 2 nanocomposites is established using Raman mapping and X-ray photoelectron spectroscopy. Corroboration of these results with absorption spectroscopy shows that lowering of direct transition of light electron conduction band to heavy hole valence band ∼2.8 and 2.95 eV is a result of the interplay between effect of electron confinement (increases band gap) and oxidation bonding environment at the surface/interface (decreases band gap) of a nanocrystal in Si-SiO 2 nanocomposites. These studies have generated deeper insight into the fundamental understanding of the nanocomposite, which can allow easy optical microscopy monitoring of Si-SiO 2 based device fabrication. [ABSTRACT FROM AUTHOR]