Theoretical Study on Structure Stability and Electronic Properties of Oxygen Dopoed BC2N Nanotubes
|School||Harbin University of Science and Technology|
|Keywords||density function theory BC2N nanotubes O-doped band structure|
B-C-N nanotubes are one of the hot topics in non-pure carbon nanotubesresearch. Among numerous B-C-N nanotubes systems, BC2N nanotubes as themost stable configuration have received much attention in recent years. However,researching about BC2N nanotubes system has not been perfect at present,especially for doping BC2N nanotubes. In this paper, therefore, BC2N nanotubesare substituted by oxygen atom common in nature to study their changes incharacter.The content of this paper is to investigate structure stability and electronicproperties of oxygen atom substituted （OB, ON, OCIand OCII） in different diameterzigzag BC2N nanotubes. Geometric structure parameters, formation energies,band structures and density of states （DOS） of pure and O-doped zigzag BC2Nnanotubes are all calculated by using the first-principle calculation method basedon the density functional theory （DFT） and by employing CASTEP softwarepackage in Material Studio4.1.The results show that geometric structures of oxygen atoms doped in zigzagBC2N nanotubes at different positions produce different effect: ONand OCIatomsare incorporated on BC2N nanotubes with negligible local deformation;nevertheless the geometric structures of OBand OCII-doped BC2N nanotubes allhave noticeable distortion. Along with the increase of the tube diameter,formation energies of O-doped BC2N nanotubes increase little by little, andstabilities decrease gradually. Among them, ON-doped （6,0） BC2N nanotubes isto be favorable, especially for the B-rich environment. In addition, bandstructures and DOS of O-doped zigzag BC2N nanotubes are changed in severalspects. Conduction bands of OBand OCI-doped BC2N nanotubes shift down globally. And their corresponding DOS peaks at the right side of Fermi level nearto the Fermi level. Both conduction bands and valence bands of ONandOCII-doped BC2N nanotubes shift down obviously. The conduction bands ofON-doped （9,0） BC2N nanotubes are moved down to the Fermi level. Comparingto pure （9,0） BC2N nanotubes, they shift down about1.8eV. The introduction ofO atoms in （9,0） BC2N nanotubes decrease energy gaps, and increase theirconductivities.