Electronic structures of porous nanocarbons

Baskin, Artem

doi:10.1038/srep00036

Cited by 41 publications

(63 citation statements)

References 36 publications

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“…However, it is still a mystery that a periodically modulated graphene can either open up a substantial gap or remain gapless (or a tiny gap) if its supercell lattice changes only slightly1819202122232425262728, which complicates the creation of bandgap by patterning and is apparently at odds with the proposal that bandgap in these graphene structures is due to quantum confinement between neighboring modulated sites16. The quantitative description of quantum confinement that results in energy gap in a patterned graphene is missing; instead, previous theoretical investigations1819202122232425262728 mainly focused on some special patterns whose supercell lattices form rectangular or hexagonal structures.…”

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confidence: 99%

Bandgap Opening by Patterning Graphene

Dvorak

Oswald

2013

Sci Rep

187

141

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Owing to its remarkable electronic and transport properties, graphene has great potential of replacing silicon for next-generation electronics and optoelectronics; but its zero bandgap associated with Dirac fermions prevents such applications. Among numerous attempts to create semiconducting graphene, periodic patterning using defects, passivation, doping, nanoscale perforation, etc., is particularly promising and has been realized experimentally. However, despite extensive theoretical investigations, the precise role of periodic modulations on electronic structures of graphene remains elusive. Here we employ both the tight-binding modeling and first-principles electronic structure calculations to show that the appearance of bandgap in patterned graphene has a geometric symmetry origin. Thus the analytic rule of gap-opening by patterning graphene is derived, which indicates that if a modified graphene is a semiconductor, its two corresponding carbon nanotubes, whose chiral vectors equal graphene's supercell lattice vectors, are both semimetals.

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confidence: 99%

Bandgap Opening by Patterning Graphene

Dvorak

Oswald

2013

Sci Rep

187

141

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“…9 On a particular note, it was demonstrated that nanopores in graphene can be fabricated with atomic precision by inducing defect nucleation centers with energetic ions, followed by edge-selective electron recoil sputtering. 10 In addition, electronic transport properties of graphene structures with specific edge designs have been studied, 8,11 and site-specific single-atom spectroscopy for direct investigation of the electronic and bonding structures of specific graphene edge atoms with atomic resolution has been carried out. 12 As an important member of the graphene device family, GNPs have been proposed as gas sensors, [13][14][15] selective sieves for ions, 16 and most notably, DNA nucleobases sensing devices promising fast and low-cost DNA sequencing.…”

Section: Introductionmentioning

confidence: 99%

Quantum conductance of armchair graphene nanopores with edge impurities

Qiu

Skafidas

2013

Journal of Applied Physics

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The quantum conductance of armchair graphene nanopores (aGNPs) with edge impurities is investigated using the tight-binding model and non-equilibrium Green's function method. We find that aGNPs are particularly interesting since their transmission spectra can be easily tuned by pore-edge shaping to produce a variety of electronic transport characteristics. We first examine the local density of states at individual impurity sites. We then study the quantum conductance of aGNPs with various transmission spectra in response to perturbations to on-site energies and hopping coefficients of edge atoms. Insights into transport properties of aGNPs are provided and implications of these findings for designing aGNP devices in interconnection and sensing applications are discussed.

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“…Unlike traditional quantum wells, the boundary conditions of GNRs are complicated functions of position and momentum resulting from the dual sublattice symmetry of graphene, giving rise to a unique band structure. Because of this, the shape of the boundary as well as the presence of nanopores profoundly affects the electronic states of GNRs (27)(28)(29)(30), for example, leading to a difference in band structure for zigzag and armchair-edged GNRs (31).…”

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Graphene quantum point contact transistor for DNA sensing

Girdhar

Sathe

Schulten

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

143

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By using the nonequilibrium Green's function technique, we show that the shape of the edge, the carrier concentration, and the position and size of a nanopore in graphene nanoribbons can strongly affect its electronic conductance as well as its sensitivity to external charges. This technique, combined with a self-consistent Poisson-Boltzmann formalism to account for ion charge screening in solution, is able to detect the rotational and positional conformation of a DNA strand inside the nanopore. In particular, we show that a graphene membrane with quantum point contact geometry exhibits greater electrical sensitivity than a uniform armchair geometry provided that the carrier concentration is tuned to enhance charge detection. We propose a membrane design that contains an electrical gate in a configuration similar to a field-effect transistor for a graphene-based DNA sensing device.O ver the past few years the need has grown for low-cost, highspeed, and accurate biomolecule sensing, propelling the socalled third generation of genome sequencing devices (1-4). Many associated technologies have been developed, but recent advances in the fabrication of solid-state nanopores have shown that the translocation of biomolecules such as DNA through such pores is a promising alternative to traditional sensing methods (5-9). Some of these methods include measuring (i) ionic blockade current fluctuations through nanopores in the presence of nucleotides (10), (ii) tunneling currents across nanopores containing biomolecules (11), and (iii) direct transversecurrent measurements (12). Graphene is a prime candidate for such measurements. Theoretical studies suggest that functionalized graphene nanopores can be used to differentiate passing ions, demonstrating the potential use of graphene membranes in nanofluidics and molecular sensing (13). In addition, its atomicscale thickness allows a molecule passing through it to be scanned at the highest possible resolution, and the feasibility of using graphene nanopores for DNA detection has been demonstrated experimentally (14-17). Lastly, electrically active graphene can, in principle, both control and probe translocating molecules, acting as a gate as well as a charge sensor, which passive, oxide-based nanopore devices are incapable of doing.Molecular dynamics studies describing the electrophoresis of DNA translocation through graphene nanopores demonstrated that DNA sequencing by measuring ionic current blockades is possible in principle (18,19). Additionally, several groups have reported first-principles-based studies to identify base pairs using tunneling currents or transverse conductance-based approaches (12,20,21). Saha et al. reported transverse edge current variations of the order of 1 μA through graphene nanoribbons (GNRs) caused by the presence of isolated nucleotides in a nanopore, and reported base pair specific edge currents (12). These studies, however, do not account for solvent or screening effects; the latter effects are due to the presence of ions in the solution and ...

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Electronic structures of porous nanocarbons

Cited by 41 publications

References 36 publications

Bandgap Opening by Patterning Graphene

Bandgap Opening by Patterning Graphene

Quantum conductance of armchair graphene nanopores with edge impurities

Graphene quantum point contact transistor for DNA sensing

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