Electronic and Optical Properties of Low-Dimensional B2CN Nanomaterials from First Principles

Abstract

The structures and electronic and optical properties of B2CN sheet and single-walled B2CN nanotubes were investigated by the first-principles density functional calculations. By rolling up the planar low-energy B2CN nanosheets along various chiral vectors, four types of zigzag and armchair B2CN nanotubes were constructed. The present calculations show that the structural and electronic properties of B-rich B2CN nanotubes strongly depend on their sizes and chiralities. The zigzag and armchair B2CN nanotubes with the small diameter generally are semiconductors, and their band gaps decrease as the tube-radius increases. When the diameter of tubes is large enough, the four kinds of nanotubes may produce the electronic behavior transitions from semiconductor to metal. Owing to the electronic affinity difference among B, C, and N atoms, there are remarkable charge transfers from B to C and N atoms in B2CN nanostructures. The predicted dielectric and optical properties show that the zigzag and armchair B2CN nanotubes are the optical anisotropy with respect to light polarization, and their absorption spectra are sensitive to the chirality of tube.