Geometric and electronic structures of monolayer hexagonal boron nitride with multi-vacancy

Abstract

Hexagonal boron nitride (h-BN) is an electrical insulator with a large band gap of 5 eV and a good thermal conductor of which melting point reaches about 3000 °C. Due to these properties, much attention was given to the thermal stability rather than the electrical properties of h-BN experimentally and theoretically. In this study, we report calculations that the electronic structure of monolayer h-BN can be influenced by the presence of a vacancy defect which leads to a geometric deformation in the hexagonal lattice structure. The vacancy was varied from mono- to tri-vacancy in a supercell, and different defective structures under the same vacancy density were considered in the case of an odd number of vacancies. Consequently, all cases of vacancy defects resulted in a geometric distortion in monolayer h-BN, and new energy states were created between valence and conduction band with the Fermi level shift. Notably, B atoms around vacancies attracted one another while repulsion happened between N atoms around vacancies, irrespective of vacancy density. The calculation of formation energy revealed that multi-vacancy including more B-vacancies has much lower formation energy than vacancies with more N-vacancies. This work suggests that multi-vacancy created in monolayer h-BN will have more B-vacancies and that the presence of multi-vacancy can make monolayer h-BN electrically conductive by the new energy states and the Fermi level shift.

Optoelectronic and elastic response of fluorinated hexagonal boron nitride monolayer

“…2) of FBNF is -0.65 eV/atom which confirms the experimental feasibility of flourination. These findings are very consistent with the previous theoretical and experimental results [42][43] [44][45] [46] . The nature of chemical bonds are analyzed by Mulliken charge density calculations (Fig.…”

Study of uniaxial tensile properties of hexagonal boron nitride nanoribbons

“…These defects impose impacts on electrical and mechanical properties of nanomaterials. [13]- [15] Sinitsii et al [16] demonstrated potassium induced splitting of BNNTs to fabricate BNNRs and there the presence of defects was also evident. Therefore, taking into account of the inevitability of structural defects, we have studied the effect of various defects on the properties of hBNNRs.…”

Boron nitride nanoscrolls: Structure, synthesis, and applications

“…It is well understood that two main contributions dominate the interlayer interaction between h-BN sheets; (1) the VDW forces for anchoring the layers at a fixed distance, and (2) the electrostatic forces dictating the optical stacking mode [59]. Here, it is worth highlighting that hBN is a wide band gap semiconductor with polar bonding [53,60,61] which typically displays completely different electronic and insulating properties in terms of applications such as usage in insulation of electric packaging [62], bandgap tailoring [63], and to increase thermal stability of epoxy composites [64]. BNS derivatives can exist in lengths ranging from a few hundred nanometers up to several microns with variable diameters, and can be envisaged as rolled up nanosheets in Archimedean spirals described by the polar equation [65]:…”