Tuning the band gap and magnetic properties of BN sheets impregnated with graphene flakes

Abstract

The BN sheet is a nonmagnetic wide-band-gap semiconductor. Using density functional theory, we show that these properties can be fundamentally altered by embedding graphene flakes. Not only do graphene flakes preserve the two-dimensional (2D) planar structure of the BN sheet, but by controlling their shape and size, unexpected electronic and magnetic properties also emerge. The electronic band structure can be tuned from a direct gap to an indirect gap, the energy gap can be further modulated by changing the bonding patterns, and both hole injecting or electron injecting can be achieved by tailoring the triangular embedding pattern. Furthermore, the Lieb theorem still holds, and the embedded triangular graphene flakes become ferromagnetic with full spin polarizations of the introduced electrons or holes, opening the door to their use as spin filters. The study sheds new light on hybrid single-atomic-layer engineering for unprecedented applications of 2D nanomaterials.

Thermal conductivity of BN-C nanostructures

“…35,36 It is recently shown that the details of the bonding at the h-BN/graphene interface can change the type of intrinsic doping of the system. 37 Just to name a few other examples of how this chemical and structural diversity in this low dimensional hybrid system enable control over magnetic properties; zigzag-edges in ribbons have been suggested to lead to ferromagnetic behavior 38 while more complex interfaces, like those present in h-BN clusters embedded in graphene, can be antiferromagnetic 39 may also be mentioned.…”

Band Gap Engineering of Hybrid 2-D Nanomaterials Some Recent Developments

“…In recent experiments, co-deposition of graphene and h-BN was attempted to form hybridized h-BNC besides synthesizing atomic layers of h-BNC by substituting C atoms in graphene layer with B and N atoms. The significance of the chemical and electrical tunability achieved in these experimental methods motivated using PECVD to synthesize several other members of h-BN derivatives [23,[26][27][28][29].…”

Formation and Physical Properties of h-BN Atomic Layers: A First-Principles Density-Functional Study

“…The h-BN monolayers embedded with triangular graphene flakes can modify the electronic properties as well as the magnetic properties [34,37]. The magnetic moments of the graphene-like flake embedded h-BN monolayer can be controlled depending on the number of the substituted C atoms in the h-BN monolayers (Figure 4), where and are the numbers of the B atoms and the N atoms replaced with the C atoms and positive and negative ( − ) values are used for the T1-C C and T2-C C structures, respectively.…”

“…The atomic vacancies in h-BN layers can be introduced using electron beam irradiations and are shown to be useful as a source of magnetism [10,[24][25][26][27]. The introductions of C atoms and graphene-like flakes into h-BN sheets have been also performed via electron beam irradiations due to analogous structural properties among B, C, and N elements [28][29][30][31][32][33][34][35][36], which can tune the electronic and the magnetic properties [37][38][39]. It is predicted theoretically that the energy band gaps are tunable depending on the size of the graphene flakes [37,38].…”

“…The introductions of C atoms and graphene-like flakes into h-BN sheets have been also performed via electron beam irradiations due to analogous structural properties among B, C, and N elements [28][29][30][31][32][33][34][35][36], which can tune the electronic and the magnetic properties [37][38][39]. It is predicted theoretically that the energy band gaps are tunable depending on the size of the graphene flakes [37,38]. The electronic transport properties of the h-BN atomic layers can be changed from insulating to conductive properties when C atoms are doped, suggesting a possibility to fabricate the novel opto/nanoelectronics applications [31,32,[34][35][36]40].…”