The possible structure and electronic structure of zigzag silicon nanotubes doped with group V elements

We performed spin-polarized density functional theory (DFT) calculations to study the stable structures and electronic structure of X-doped (X = N, P, As, Sb and Bi) single-walled silicon nanotubes (SiNTs). Intrinsic SiNTs with small diameters can exist stably and maintain a smooth surface structure. However, due to the addition of impurities, small-diameter nanotubes cannot maintain a stable tube structure. In addition to Bi, the doping of group five elements can effectively improve the stability of (14, 0) SiNTs. Moreover, the addition of group V elements makes SiNTs produce impurity levels at the Fermi level, thereby reducing the band gap. The doping of P, As, Sb, and Bi even led to the transformation of SiNTs from semiconductors to metals, and the energy level shift appears in N-doped SiNTs.