The effect of carbon chain doping at different positions on the electrical properties of bilayer silicene nanoribbons

Atom doping is widely present in graphene and silicene materials, which can effectively regulate the electrical properties of nanostructures. In this paper, the effects of doping carbon atoms at different positions on the geometric structure and electrical properties of bilayer zigzag silicene nanoribbons (ZSiNRs) with different widths were studied by self-consistent charge density functional tight-binding (SCC-DFTB) method. Carbon doping in silicene nanoribbons induces a local reconstruction, amplifies surface warpage, and boosts interlayer interactions. The width of the nanoribbons and the position and concentration of the doped carbon atoms significantly affect the stability of the bilayer silicene nanoribbons, which can effectively regulate its band gap. Especially when carbon atoms are doped at the edge, the width of the band gap can be effectively increased. Different doping positions and concentrations can cause nanoribbons to exhibit three properties: metallic, semi-metallic, and semiconducting. The doping position and concentration of carbon atoms significantly affect the charge transfer of silicene nanoribbons. In general, the charge is always transferred from silicon atoms to carbon atoms.