Electronic states and luminescence in higher fullerene/porous Si nanocrystal composites

Photoluminescence (PL) measurements have been performed on the nanocomposites of higher fullerene-coupled porous silicon (PS) nanocrystals. For the C70 PS and C76 (78) PS nanocomposites, the PL spectra show a pinning wavelength at ∼565 nm and for the C84 PS and C94 PS nanosystems the pinning wavelength is at ∼590 nm. The PL pinning property is closely related to the sorts of the coupled fullerenes. A band mixing model of direct and indirect gaps in a nanometer environment consisting of nc-Si core, Si O2 surface layer, and coupled fullerene has been proposed for calculation of electronic states. Good agreement is achieved between the experiments and theory. © 2006 American Institute of Physics.