Polymerization of Silicon-Doped Heterofullerenes: an Ab Initio Study

We perform the calculations on geometric and electronic structures of Si-doped heterofullerene C₅₀Si₁₀ and its derivatives, a C₄₀Si₂₀-C₄₀Si₂₀ dimer and a C₄₀Si₂₀-based nanowire by using density-functional theory. The optimized configuration of the C₄₀Si₂₀-based nanowire exhibits a regular dumbbell-shaped chain nanostructure. The electronic structure calculations indicate that the HOMO--LUMO gaps of the heterofullerene-based materials can be greatly modified by substitutionally doping with Si atoms and show a decreasing trend with increase cluster size. Unlike the band structures of the
conventional wide band gap silicon carbide nanomaterials, the C₄₀Si₂₀-based nanowire has a very narrow direct band gap of 0.087eV.