Energetics and structural properties of adsorbed atoms and molecules on silicon-doped carbon nanotubes

The energetics and structural properties of atoms and molecules on a substitutional Si atom in single wall carbon nanotubes (SWCN) are investigated using first principle calculations based on density-functional theory. A detailed analysis is performed for the geometry and the electronic structures of a Si-doped semiconducting (10,0) carbon nanotube interacting with F, Cl, H, CH3, and SiH3. A common feature for the systems with these atoms or molecules is the presence of one half-filled level close to the top of the valence band. The specific position of this level in the gap depends on the chemisorbed species and the binding energy between this species and the Si atom.