Tunable doping and band gap of graphene on functionalized hexagonal boron nitride with hydrogen and fluorine

Abstract

First-principles calculations have been used to investigate the structural and electronic properties of graphene supported on functionalized hexagonal boron nitride (h-BN) with hydrogen and fluorine atoms. Our results show that the hydrogenation and fluorination of the h-BN substrate modify the electronic properties of graphene. Interactions of graphene with fully hydrogenated or fully fluorinated h-BN and half-hydrogenated and half-fluorinated h-BN with H at N sites and F at the B sites can lead to n- or p-type doping of graphene. The different doping effect may be attributed to the significant charge transfer from graphene to the substrate. Interestingly, when graphene is supported on the functionalized h-BN with H at B sites and F at N sites (G/HBNF), a finite band gap of 79 meV in graphene is opened due to the equivalence breaking of two sublattices of graphene, and can be effectively modulated by changing the interlayer spacing, increasing the number of functionalized BN layers, and applying an external electric field. More importantly, the modification of the band gap in G/HBNF with a functionalized BN bilayer by the electric field is more pronounced than that of the single-layer h-BN, which is increased to 408 meV with 0.8 V Å(-1). Thus, graphene on chemically modified h-BN with a tunable and sizeable band gap may provide a novel way for fabricating high-performance graphene-based nanodevices.

Tunable band gap of MoS2-SiC van der Waals heterostructures under normal strain and an external electric field

“…Such exotic phenomena have never been observed in other vdW heterostructures. [14][15][16] The band structure calculations (Fig. 7) show that under the positive electric field, ranging from 0.0 to +0.18 V/Å, both the conduction band minimum (CBM) and the valence band maximum (VBM) shift to the Fermi level as the E-field strength increases, then the band gap becomes smaller and eventually disappears.…”

“…[12][13][14][15][16][17] For example, monolayer graphene remains a zero-gap material under an external electric field but a finite band gap appears for bilayer and multilayer graphene. 18,19 Because of the impressive progress in graphene research, enormous scientists have focused on exploring other 2D materials.…”

Bipolar doping of double-layer graphene vertical heterostructures with hydrogenated boron nitride

“…The calculated work function W Gr is 4.3 eV, which is slightly lower than the experimental value (4.6 eV). 15 Though many previous calculations have focused on the single side doping graphene by stacking on various two dimensional material substrates 16,36,39 (e.g., hexagonal BN and hydrogenated/fluorinated graphene), the doping mechanisms of those interfaces are different from our bipolar doping case. This indicates that W Gr/n(p) was increased due to other dipole contributions, such as the surface dipoles and chemical interactions.…”

Computational chemistry for graphene-based energy applications: progress and challenges

“…154 It has also been shown that it is possible to tune the band gap of C/BN HBLs, theoretically, by functionalising the h-BN sheet with hydrogen and fluorine. 147 The incorporation of B or N atoms into lattice is another way to dope graphene. [139][140][141][142]155,156 The swapping of a single C atom for a B atom or a N atom will shift the Fermi level downwards (p-doping) or upwards (n-doping), respectively.…”