Electric field effect in boron and nitrogen doped graphene bilayers

Nemneş, George Alexandru; Mitran, T. L.; Manolescu, Andrei; Dragoman, Daniela

doi:10.1016/j.commatsci.2018.08.054

Cited by 14 publications

(8 citation statements)

References 40 publications

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“…Basically, the opening of a bandgap in graphene is achieved by a symmetry breaking of the hexagonal structure of graphene [17]. Therefore, several methods have been proposed to break the high symmetry of monolayer and bilayer graphene, such as strain [18,19], magnetic field [20], oxidation [21], application of a transverse electric field [22,23], chemical modification [24,25], and doping processes [26,27,28].…”

Section: Introductionmentioning

confidence: 99%

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

et al. 2020

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We model boron and nitrogen doped/codoped monolayer graphene to study its stability, interaction energy, electronic and thermal properties using density functional theory. It is found that a doped graphene sheet with non-bonded B or N atoms induces an attractive interaction and thus opens up the bandgap. Consequently, the power factor is enhanced. Additionally, bonded B or N atoms in doped graphene generate a repulsive interaction leading to a diminished bandgap, and thus a decreased power factor. We emphasis that enhancement of the power factor is not very sensitive to the concentration of the boron and nitrogen atoms, but it is more sensitive to the positions of the B or N atoms in ortho, meta, and para positions of the hexagonal structure of graphene. In the B and N codoped graphene, the non-bonded dopant atoms have a weak attractive interaction and interaction leading to a small bandgap, while bonded doping atoms cause a strong attractive interaction and a large bandgap. As a result, the power factor of the graphene with non-bonded doping atoms is reduced while it is enhanced for graphene with bonded doping atoms.

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Section: Introductionmentioning

confidence: 99%

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

et al. 2020

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“…3, for zero electric field and an electric field | E field | = 5 V/nm perpendicular to the graphene sheets, with the two possible orientations. The position of the energy gap is systematically modified by the external electric field, as already indicated for B and N doped BLGs [21]. The gaps introduced by either B or N substitutions were also found in the context of disorder using the random tight-binding model [40].…”

Section: B Electronic Propertiesmentioning

confidence: 61%

“…In this paper we are particularly focused on the combined effect of doping and external electric field. We already showed that the effective doping by boron or nitrogen can be systematically modified by an applied electric field [21]. It was also established that dual doping by B and N, opens a gap at zero field in a BLG system.…”

Section: Introductionmentioning

confidence: 94%

“…Because in doped graphenes the gap size is rather small (0.25 eV) and the electric field required is large, the use of intrinsic BLG is less practical, in spite of the gap tunability. Therefore, in pursuing the gap enhancement in BLGs, similar to the case of monolayer graphene, several methods have been considered, such as doping [16][17][18][19][20][21], functionalization [22,23] or substrate influence [24,25]. * nemnes@solid.fizica.unibuc.ro Chemical doping of BLGs was further explored from different perspectives.…”

Section: Introductionmentioning

confidence: 99%

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Electric and thermoelectric properties of graphene bilayers with extrinsic impurities under applied electric field

Nemneş

Mitran

Manolescu

et al. 2019

Physica B: Condensed Matter

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In contrast to monolayer graphene, in bilayer graphene (BLG) one can induce a tunable bandgap by applying an external electric field, which makes it suitable for field effect applications. Extrinsic doping of BLGs enriches the electronic properties of the graphene-based family, as their behavior can be switched from an intrinsic small-gap semiconductor to a degenerate semiconductor. In the framework of density functional theory (DFT) calculations, we investigate the electronic and thermoelectric properties of BLGs doped with extrinsic impurities from groups III (B, Al, Ga), IV (Si, Ge) and V (N, P, As), in the context of applied external electric fields. Doping one monolayer of the BLG with p-or n-type dopants results in a degenerate semiconductor, where the Fermi energy depends on the type of the impurity, but also on the magnitude and orientation of the electric field, which modifies the effective doping concentration. Doping one layer with isoelectronic species like Si and Ge opens a gap, which may be closed upon applying an electric field, in contrast to the pristine BLG. Furthermore, dual doping by III-V elements, in a way that the BLG system is formed by one n-type and one p-type graphene monolayer, leads to intrinsic semiconductor properties with relatively large energy gaps. Si-Si and Ge-Ge substitutions render a metallic like behavior at zero field similar to the standard BLG, however with an asymmetric density of states in the vicinity of the Fermi energy. We analyze the suitability of the highly doped BLG materials for thermoelectric applications, exploiting the large asymmetries of the density of states. In addition, a sign change in the Seebeck coefficient is observed by tuning the electric field as a signature of narrow bands near the Fermi level.

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“…The electronic properties of a BLG have been studied using density functional theory (DFT), in which the bandgap at the K point in the Brillouin zone depends linearly on the average applied electric field [9,10]. One of the main approaches to alter the electrostatic potential of a BLG is substitutional doping with foreign atoms [11] such as Boron (B), Nitrogen (N) [12], and Silicon (Si) atoms. For instant, a B-and N-doped BLG results in a p-type or an ntype semiconducting behavior with a shifting of the Fermi energy, respectively.…”

Section: Introductionmentioning

confidence: 99%

Interlayer interaction controlling the properties of AB- and AA-stacked bilayer graphene-like BC$_{14}$N and Si$_{2}$C$_{14}$

Abdullah,

Rashid,

Manolescu

et al. 2020

Preprint

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We model bilayer graphene-like materials with Si 2 C 14 and BC 14 N stoichiometry, where the interlayer interactions play important roles shaping the physical properties of the systems. We find the interlayer interaction in Si 2 C 14 to be repulsive due to the interaction of Si-Si atoms, and in BC 14 N it is attractive due to B and N atoms for both the AA-and the AB-stacking. The repulsive interlayer interaction opens up a bandgap in Si 2 C 14 while the attractive interlayer interaction in BC 14 N induces a small indirect bandgap or overlaping of the valence conduction bands. Furthermore, the repulsive interaction decreases the Young modulus while the attractive interaction does not influence the Young modulus much.The stress-strain curves of both the AA-and the AB-stackings are suppressed compared to pure graphine bilayers. The optical response of Si 2 C 14 is very sensitive to an applied electric field and an enrichment in the optical spectra is found at low energy. The enrichment is attributed to the bandgap opening and increased energy spacing between the π-π * bands. In BC 14 N, the optical spectra are reduced due to the indirect bandgap or the overlapping of the π-π * bands. Last, a high Seebeck coefficient is observed due to the presence of a direct bandgap in Si 2 C 14 , while it is not much enhanced in BC 14 N.

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Electric field effect in boron and nitrogen doped graphene bilayers

Cited by 14 publications

References 40 publications

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

Effects of bonded and non-bonded B/N codoping of graphene on its stability, interaction energy, electronic structure, and power factor

Electric and thermoelectric properties of graphene bilayers with extrinsic impurities under applied electric field

Interlayer interaction controlling the properties of AB- and AA-stacked bilayer graphene-like BC$_{14}$N and Si$_{2}$C$_{14}$

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