ELECTRONIC-STRUCTURE OF AMORPHOUS-SILICON NANOCLUSTERS

The electronic structure of amorphous silicon nanoclusters is calculat ed within the empirical tight-binding approximation. The electronic st ates are classified into three groups: extended and weakly and strongl y localized. The last category practically disappears in hydrogenated amorphous silicon clusters for which the blueshift is comparable to wh at is predicted for crystallites. The radiative recombination rates ar e comparable for small clusters (similar to 1 nm) but 2 orders of magn itude higher for larger clusters (similar to 2 nm) of the amorphous ph ase due to disorder induced breaking of selection rules.