Control of silicon dimensionality of polysilanes and their optical properties

The effects of the silicon skeleton on the optical properties were studied for various kinds of polysilanes such as polysilylene, polysilyne, and soluble organosilicon nanocluster, which have one, two, and three dimensional silicon skeletons, respectively. The absorption and emission spectra of the polysilanes show the decrease of the optical band gap E_g,opt with increasing the Si-dimensionality. The quantum size effects in the optical properties of the organosilicon nanoclusters with various Si-core sizes were discussed in comparison with those of inorganic silicons. E_g,opt of the organosilicon nanocluster film heat-treated at 500°C is similar to that of a-Si, and it suggests the possibility of a-Si coating.