Erratum:<i>Ab initio</i>investigation of molecular hydrogen physisorption on graphene and carbon nanotubes [Phys. Rev. B<b>75</b>, 245413 (2007)]

Henwood, Daniel; Carey, J. D.

doi:10.1103/physrevb.76.049901

Cited by 47 publications

(83 citation statements)

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“…The GGA-PBE functional predicts that the H 2 dimer binds at a distance of about 3.90 Å away from the layer (measured either inside (I) or outside (O) the bilayer). This value suggests that the dimer is further away from the layer compared to that predicted by non-local vdW corrections where the dimer is about 2.80 Å (which is in agreement with LDA results 63 ). It must be noted that the LDA results were obtained when a H 2 dimer was physisorbed on single layer graphene.…”

Section: B Stability Analysis and Structural Propertiessupporting

confidence: 80%

Van der Waals density-functional study of 100% hydrogen coverage on bilayer graphene

Mapasha

Andrew

Chetty

2013

Computational Materials Science

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We investigate all hydrogen configurations that exist in a 1×1 unit cell of bilayer graphene at 100% coverage to find the low energy competing configurations using density functional theory (DFT). Other unique configurations, obtained from a 2×1 supercell, are also investigated. The GGA-PBE functional and four variants of non-local van der Waals density functionals namely, vdW-DF, vdW-DF2, vdW-DF-C09 x , and vdW-DF2-C09 x are used to account for the exchange correlation effects. Ten unique hydrogen configurations are identified for 1×1 unit cell bilayer graphene, and nine of these structures are found to be energetically stable with three low energy competing configurations. One arrangement found to exist in both 1×1 and 2×1 cell sizes is the most energetically stable configuration of all considered. For some of the configurations identified from the 2×1 supercell, it is found that the effect of hydrogenation results in greatly distorted hexagonal layers resulting in unequal bond distances between the carbon atoms. Also, interaction between the hydrogen-decorated planes greatly affects the energetics of the structures. The vdW-DF-C09 x functional is found to predict the shortest interlayer distances for all the configurations, whereas the GGA-PBE functional predicts the largest. For the most energetically favorable configuration, hydrogenation is found to reduce the elastic properties compared with pristine bilayer graphene.

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Section: B Stability Analysis and Structural Propertiessupporting

confidence: 80%

Van der Waals density-functional study of 100% hydrogen coverage on bilayer graphene

Mapasha

Andrew

Chetty

2013

Computational Materials Science

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“…The efficiency of this basis set has recently being examined in detail [16] for hydrogen and carbon and compared with other basis sets and found to be of sufficient in terms of a negligible basis set superposition error. In the case of adsorption on graphene, a hexagonal plate of 96 sp 2 bonded carbon atoms was chosen [17]. The bond lengths for the graphene layer were 0.142 nm which agrees with the experimental values of 0.141 nm.…”

Section: Simulation Detailssupporting

confidence: 67%

Molecular physisorption on graphene and carbon nanotubes: a comparative ab initio study

Henwood

Carey

2008

Molecular Simulation

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The results of ab initio density functional theory calculations of molecular physisorption on a number of different adsorption sites on a graphene sheet and on a (10, 0) single walled carbon nanotube are discussed. Both the Vosko-Wilk-Nusair (VWN) local density approximation (LDA) functional and the Perdew-Wang (PW91) generalized gradient approximation (GGA) functional were employed in calculating the binding energy of a hydrogen molecule to the appropriate carbon nanostructure as well as the optimal molecule -nanostructure separation. Both exterior and interior nanotube adsorption sites were examined and it is shown that the binding energy associated with interior adsorption sites is larger than exterior adsorption on the nanotube or onto the graphene layer. The use of carbon nanostructures for hydrogen storage is also discussed.

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“…The size of a molecular hydrogen is expected to be about 0.15nm, which is smaller than the gold contact equilibrium separation. 23 So it is plausible to expect that some molecules are allowed to diffuse and position between the metal-graphene interface. This hypothesis is also likely to happen, since gold has a low H2 diffusion coefficient 31 and does not react 32 with H2.…”

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confidence: 99%

“…Indicating that the molecular hydrogen does not transfer charge or react with the graphene channel, as expected. 23,24 Meanwhile, for invasive configuration, the total resistance changes in an asymmetric manner when the sample is exposed to H2. Fig.…”

mentioning

confidence: 99%

Metal-graphene heterojunction modulation via H2 interaction

Cadore

Mania

Morais

et al. 2016

Applied Physics Letters

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Combining experiment and theory, we investigate how a naturally created heterojunction (pn junction) at a graphene and metallic contact interface is modulated via interaction with molecular hydrogen (H2). Due to an electrostatic interaction, metallic electrodes induce pn junctions in graphene, leading to an asymmetrical resistance for electronic transport via electrons and holes. We report that an asymmetry in the resistance can be tuned in a reversible manner by exposing graphene devices to H2. The interaction between the H2 and graphene occurs solely at the graphene-contact pn junction and might be due to a modification on the electrostatic interaction between graphene and metallic contacts. We confront the experimental data with theory providing information concerning the length of the heterojunction, and how it changes as a function of H2 adsorption. Our results are valuable for understanding the nature of the metal-graphene interfaces and point out to a novel route towards selective hydrogen sensor application.Graphene is a zero-gap semiconductor which charge carrier density and conductance can be controlled electrostatically by preparing graphene devices as field effect transistors.1,2 In such architecture, the contact resistance considerably impairs device performance and is responsible for a conduction asymmetry for p-doped and n-doped graphene.3-8 This asymmetry stems from heterojunctions (pn junctions) formed at metal-graphene interfaces due to different work functions between graphene and metal -i.e. Fermi level pinning. 9-13 Effectively, the advent of the pn junction results in an additional charge scattering at the metal-graphene interface increasing device resistance. On the other hand, interesting effects can be observed as well. For instance: heterojunctions at metal-graphene interface have been used to design FabryPerot cavities 11 and to observe resonances in Josephson junctions in graphene devices. 14 In both systems, the metal-graphene interfaces have been considered a static problem, where the doping at the graphene underneath the contact is solely defined by the type of metal used. However, so far, a controllable method to probe and modulate the pn junction induced by contacts has not been reported. In addition, there are still open questions about how far a pn junction can extend from the contact into the graphene channel and if there are technological applications based on specialties of graphene contact resistance. 3,4,6,7,[14][15][16]

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Erratum:Ab initioinvestigation of molecular hydrogen physisorption on graphene and carbon nanotubes [Phys. Rev. B75, 245413 (2007)]

Abstract: Erratum: Ab initio investigation of molecular hydrogen physisorption on graphene and carbon nanotubes [Phys. Rev. B 75, 245413 (2007)]

Cited by 47 publications

References 0 publications

Van der Waals density-functional study of 100% hydrogen coverage on bilayer graphene

Van der Waals density-functional study of 100% hydrogen coverage on bilayer graphene

Molecular physisorption on graphene and carbon nanotubes: a comparative ab initio study

Metal-graphene heterojunction modulation via H2 interaction

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