Electronic properties tuning of defective heterostructured CBN nanotubes by uniaxial pressure: a density functional study

The effects of uniaxial pressure on the electronic properties of Stone-Wales (SW) defective heterostructured carbon and boron nitride (CBN) nanotubes were studied by density functional theory. Stone-Wales defects were modeled on a single-walled (9,0) zigzag CBN nanotube; at the boron nitride (BN) segment (Type-I), the carbon (C) segment (Type-II), and at the interface of the carbon and the boron nitride segments (Type-III). The calculated bandgap value is found to be dependent on the location of the SW defect. While the carbon segment dominates the bandgap response of the CBN nanotube to the applied uniaxial pressure, introducing the Stone-Wales defects shows varying responses in the bandgap. We found that the bandgap of the BN segment (Type-I) is barely affected by the applied pressure due to the strong covalent bonds of the SW defect. However, the observed changes in the bandgap values in Type-II and Type-III models can be attributed to shifts in the dispersion k vector positions and the CB, CN, and CC bonds formed by the SW defects. Our calculations further reveal that the energy gap is a direct semiconductor gap for all understudy models. Additionally, the effects of applying uniaxial pressure on Fermi energy, charge distributions, and total energy were investigated. Finally, we believe tuning the electronic properties of SW defective BCN heterostructures will open new opportunities for optical and electronic nanodevices.

Automated summary

The position of Stone-Wales defects on carbon boron nitride nanotubes affects their bandgap values, with the carbon segment dominating the response to uniaxial pressure. While the bandgap of the boron nitride segment is barely affected by pressure, the interface between the boron nitride and carbon segments shows unique changes in bandgap values.