Supramolecular Assemblies Formed on an Epitaxial Graphene Superstructure

Pollard, Andrew J.; Perkins, Edward W; Smith, Nicholas A.; Saywell, Alex; Goretzki, Gudrun; Phillips, Anna G.; Argent, Stephen P.; Sachdev, Hermann; Müller, Frank; Hüfner, S.; Gsell, S.; Fischer, Martin C.; Schreck, M.; Osterwalder, Jürg; Greber, Thomas; Berner, Simon; Champness, Neil R.; Beton, Peter H.

doi:10.1002/anie.200905503

Cited by 110 publications

(76 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of moiré patterns not only implies changes in the graphene morphology but also in its electron density, which is no longer uniform [4]. This non uniform electron density is responsible for, e.g., the formation of quantum dots [15,16] or the selective deposition of organic molecules on well defined regions of the graphene sheet [17,18].In spite of the efforts to determine the structural corrugation of the moiré observed in G=Ru, the actual value of such corrugation is still a subject of controversy. Low energy electron diffraction (LEED) experiments give a corrugation of 1.5 Å [19], while surface x-ray diffraction (SXRD) measurements suggest two possible values, 0.82 and 1.5 Å [6,20].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Role of Dispersion Forces in the Structure of Graphene Monolayers on Ru Surfaces

et al. 2011

View full text Add to dashboard Cite

Elaborate density functional theory (DFT) calculations that include the effect of van der Waals (vdW) interactions have been carried out for graphene epitaxially grown on Ru(0001). The calculations predict a reduction of structural corrugation in the observed moiré pattern of about 25% ($ 0:4 # A) with respect to DFT calculations without vdW corrections. The simulated STM topographies are close to the experimental ones in a wide range of bias voltage around the Fermi level. DOI: 10.1103/PhysRevLett.106.186102 PACS numbers: 73.22.Pr, 68.37.Ef, 68.55.Àa, 71.15.Mb The exceptional electronic properties of perfect twodimensional graphene, such as its high electron mobility or its anomalous quantum Hall effect [1], makes it a promising material for applications in microelectronics and sensing. In practice, synthesis of graphene can be achieved by epitaxial growth of carbon monolayers on transition metals [2][3][4][5]. This has stimulated a lot of experimental work on different metal substrates [4,[6][7][8][9][10][11][12][13][14], which has already led to the production of relatively large domains (a crucial aspect to reproduce the properties of infinitely planar graphene). Nevertheless, in most cases, the presence of the substrate leads to modifications of the graphene morphology. One of these is the appearance of moiré patterns [3], as it is the case for graphene grown on Ru(0001) (G=Ru for short). The presence of moiré patterns not only implies changes in the graphene morphology but also in its electron density, which is no longer uniform [4]. This non uniform electron density is responsible for, e.g., the formation of quantum dots [15,16] or the selective deposition of organic molecules on well defined regions of the graphene sheet [17,18].In spite of the efforts to determine the structural corrugation of the moiré observed in G=Ru, the actual value of such corrugation is still a subject of controversy. Low energy electron diffraction (LEED) experiments give a corrugation of 1.5 Å [19], while surface x-ray diffraction (SXRD) measurements suggest two possible values, 0.82 and 1.5 Å [6,20]. In scanning tunneling microscopy (STM) measurements, the apparent corrugation of the moiré ripples decreases from 1.1 to 0.5 Å when the tunneling bias voltage goes from À0:8 V to þ0:8 V [21]. Helium atom scattering (HAS) experiments, that are sensitive to the surface total charge corrugation, give 0.15-0.4 Å [22]. On the theoretical side, density functional theory (DFT) calculations [19,[23][24][25][26], in which the C and Ru high symmetry directions are aligned but the unit cell is large enough to account for the moiré pattern, predict a corrugation in the range $1:5-1:7 # A [23-25]. In the latter calculations, the effect of van der Waals (vdW) or dispersion forces could not be included. However, there is strong evidence that these forces play a crucial role in the adsorption of aromatic molecules on metal surfaces [27][28][29][30][31], leading, in comparison with nonvdW DFT calculations, to a significant increase of adsorpti...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Role of Dispersion Forces in the Structure of Graphene Monolayers on Ru Surfaces

et al. 2011

View full text Add to dashboard Cite

show abstract

“…For single layers of graphene, the main structural parameters are registry with and distance to the substrate that have a decisive influence on the electronic properties [1][2][3][4] and the functionality [5][6][7][8]. Such systems are commonly called moiré superstructures.…”

mentioning

confidence: 99%

Moiré beatings in graphene on Ru(0001)

Iannuzzi

Kalichava

et al. 2013

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

The moiré superstructure of a single layer of carbon on ruthenium, where 25×25 graphene honeycombs sit on 23×23 substrate unit cells, is determined from first principles. The density functional theory (DFT) calculations predict two kinds of structural units, Ω and Y, in the supercell, which are identified as moiré beatings or moirons. The related topographic bucklings, or "hills," have distinct carbon conformations and a height of 1.16 Å. The different moirons are observed with scanning tunneling microscopy (STM), and surface x-ray diffraction (SXRD) also discriminates the two. This connects ab initio DFT calculations with STM and SXRD experiments in unit cells containing more than 4000 atoms.

show abstract

“…In the present case, two possible mechanisms might be responsible for the site and orientation preference: the variation of local work function [33], and charge redistribution-induced lateral electric field. Our DFT calculation rules out the former one, because its effect on both types of molecules is inconsistent with the experimental observations [16].…”

Section: Site and Orientation Preferential Adsorption Behaviour Of Ormentioning

confidence: 82%

Constructing molecular structures on periodic superstructure of graphene/Ru(0001)

Wang

et al. 2014

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

We review the way to fabricate large-scale, high-quality and single crystalline graphene epitaxially grown on Ru(0001) substrate. A moiré pattern of the graphene/Ru(0001) is formed due to the lattice mismatch between graphene and Ru(0001). This superstructure gives rise to surface charge redistribution and could behave as an ordered quantum dot array, which results in a perfect template to guide the assembly of organic molecular structures. Molecules, for example iron phthalocyanine and C 60 , on this template show how the molecule–substrate interaction makes different superstructures. These results show the possibility of constructing ordered molecular structures on graphene/Ru(0001), which is helpful for practical applications in the future.

show abstract

Supramolecular Assemblies Formed on an Epitaxial Graphene Superstructure

Cited by 110 publications

References 58 publications

Role of Dispersion Forces in the Structure of Graphene Monolayers on Ru Surfaces

Role of Dispersion Forces in the Structure of Graphene Monolayers on Ru Surfaces

Moiré beatings in graphene on Ru(0001)

Constructing molecular structures on periodic superstructure of graphene/Ru(0001)

Contact Info

Product

Resources

About