Structural and optical behavior of single-walled and multi-walled boron nitride nanotubes

Abstract

Using Density Functional Theory (DFT), the structural, electrical, and optical properties of single-walled boron nitride nanotubes (SWBNNTs), double-walled boron nitride nanotubes (DWBNNTs), and multi-walled boron nitride nanotubes (MWBNNTs) was investigated. The calculated cohesive energy shows that the double-walled and multi-walled BNNTs are more stable than the single-walled BNNTs they are made up of. All of the simulated nanotubes have semiconducting behavior, according to the electronic properties. The interaction between the 2pz orbitals of the internal and external nanotubes reduces the band gaps (Eg) of the DWBNNTs and MWBNNTs. Furthermore, in the 5.8 to 6.5 eV energy range, the z component of the refractive index for SWBNNTs approaches a minimum. DWBNNTs and MWBNNTs, on the other hand, have a nz minimum in the lower energy range (=4.8–5.5 eV). SWBNNTs (4, 4) have an optical absorption similar to single-walled carbon nanotubes. SWBNNTs (4, 4) have an optical absorption similar to single-walled carbon nanotubes. Moreover, the z component of the optical absorption fell from 600,000 cm−1 for SWBNNTs (4, 4) to 30,000 cm−1 for MWBNNTs (4, 4) @ (8, 8) @ (12, 12).