Band gap modulation of bilayer graphene by single and dual molecular doping: A van der Waals density-functional study

Hu, Tao; Gerber, Iann C.

doi:10.1016/j.cplett.2014.10.034

Cited by 12 publications

(10 citation statements)

References 52 publications

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“…Tightbinding models have been also employed in the description of doped BLG systems [20,21]. Furthermore, in the absence of an electric field the gap of BLG can be chemically tuned by doping [22,23,24] and functionalization [25,26]. Applying strain on doped BLG is another approach, by which the mechanically tunable electronic energy gap can be achieved [27].…”

Section: Introductionmentioning

confidence: 99%

Electric field effect in boron and nitrogen doped graphene bilayers

Nemneş

Mitran

Manolescu

et al. 2018

Computational Materials Science

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Unlike single layer graphene, in the case of AB-stacked bilayer graphene (BLG) one can induce a non-zero energy gap by breaking the inversion symmetry between the two layers using a perpendicular electric field. This is an essential requirement in field-effect applications, particularly since the induced gap in BLG systems can be further tuned by the magnitude of the external electric field. Doping is another way to modify the electronic properties of graphene based systems. We investigate here BLG systems doped with boron and nitrogen in the presence of external electric field, in the framework of density functional theory (DFT) calculations. Highly doped BLG systems are known to behave as degenerate semiconductors, where the Fermi energy depends on the doping concentration but, in addition, we show that the electronic properties drastically depend also on the applied electric field. By changing the magnitude and the orientation of the electric field, the gap size and position relative to the Fermi level may be tuned, essentially controlling the effect of the extrinsic doping. In this context, we discuss in how far the external electric field may suitably adjust the effective doping and, implicitly, the conduction properties of doped BLG systems.

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Section: Introductionmentioning

confidence: 99%

Electric field effect in boron and nitrogen doped graphene bilayers

Nemneş

Mitran

Manolescu

et al. 2018

Computational Materials Science

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“…At these metal contacts, interfacial CT should naturally occur because the Fermi level of the electrodes and the underlying BLG layer should be aligned. While the CT from surface adsorbates with a high ionization potential or low electron affinity has been well documented [6,7,[13][14][15], the CT from 3 conventional electrode metals has been investigated less [16,17].…”

Section: Introductionmentioning

confidence: 99%

Contact resistance at planar metal contacts on bilayer graphene and effects of molecular insertion layers

Nouchi

2017

Nanotechnology

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The possible origins of metal-bilayer graphene (BLG) contact resistance are investigated by taking into consideration the bandgap formed by interfacial charge transfer at the metal contacts.Our results show that a charge injection barrier (Schottky barrier) does not contribute to the contact resistance because the BLG under the contacts is always degenerately doped. We also showed that the contact-doping-induced increase in the density of states (DOS) of BLG under the metal contacts decreases the contact resistance owing to enhanced charge carrier tunnelling at the contacts. The contact doping can be enhanced by inserting molecular dopant layers into the metal contacts. However, carrier tunnelling through the insertion layer increases the contact resistance, and thus, alternative device structures should be employed. Finally, we showed that the inter-band transport by variable range hopping via in-gap states is the largest contributor to contact resistance when the carrier type of the gated channel is opposite to the contact doping carrier type. This indicates that the strategy of contact resistance reduction by the contact-doping-induced increase in the DOS is effective only for a single channel transport branch (n-or p-type) depending on the contact doping carrier type. 2

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“…61,62 This particular choice of exchange-correlation functional is based on several previous works. [63][64][65][66][67] All the atoms were allowed to relax until the maximum of all forces acting on them became smaller than 0.02 eV.Å −1 . The k-point sampling was always based on a Γ-centered grid for all types of calculations.…”

Section: Electronic Propertiesmentioning

confidence: 99%

Polymorphism of Two-Dimensional Halogen Bonded Supramolecular Networks on a Graphene/Iridium(111) Surface

et al. 2017

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The properties of 2D supramolecular self-assemblies on surfaces depend on the fine balance between molecule-substrate and molecule-molecule interactions. In this article, we study the growth of 1,3,5-tri(4'-bromophenyl)benzene (TBB) monolayer on graphene epitaxially grown on Ir(111) by means of low temperature scanning tunneling microscopy and spectroscopy (LT-STM/STS) combined with a fully atomistic 1 description of the molecules in interaction with the Gr/Ir(111) substrate, using density functional theory (DFT). In order to figure out the impact of the underlying metallic layer upon the self-assembling behavior of the molecules and their properties, we compare our results with those theoretically obtained on pristine graphene or experimentally achieved on HOPG. We demonstrated that the use of the Ir layer allows the formation of large extended, continuous and two-dimensional supramolecular networks laying even over Ir step edges like a carpet. In addition, we highlighted the obtention of two structural polymorphs never observed on HOPG. In the light of DFT simulations, we assumed that the formation of these polymorphs is driven by the balance between molecule-molecule interactions, due to Halogen bonds (XB), and the tailored molecule-surface interactions due to the presence of Ir layer.

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Band gap modulation of bilayer graphene by single and dual molecular doping: A van der Waals density-functional study

Cited by 12 publications

References 52 publications

Electric field effect in boron and nitrogen doped graphene bilayers

Electric field effect in boron and nitrogen doped graphene bilayers

Contact resistance at planar metal contacts on bilayer graphene and effects of molecular insertion layers

Polymorphism of Two-Dimensional Halogen Bonded Supramolecular Networks on a Graphene/Iridium(111) Surface

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