Edge state effects in junctions with graphene electrodes

Ryndyk, Dmitry A.; Bundesmann, Jan; Liu, Ming‐Hao; Richter, Klaus

doi:10.1103/physrevb.86.195425

Cited by 23 publications

(29 citation statements)

References 42 publications

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“…Graphene is especially interesting as it can be produced in large scale through chemical vapor deposition (CVD) [19][20][21] or growth on silicon carbide 22 , a prerequisite to gather the large statistics required in molecular electronics investigations. Graphene as an electrode material for contacting molecules has been the subject of various theoretical studies [23][24][25] . First experiments using CNTs 9-11 , few-layer graphite [12][13][14] and CVD graphene 15,16 show that sp 2 carbon electrodes are stable and allow gating, optical and chemical access.…”

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confidence: 99%

High-yield fabrication of nm-size gaps in monolayer CVD graphene

et al. 2014

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Herein we demonstrate the controlled and reproducible fabrication of sub-5 nm wide gaps in single-layer graphene electrodes. The process is implemented for graphene grown via chemical vapor deposition using an electroburning process at room temperature and in vacuum. A yield of over 95% for the gap formation is obtained. This approach allows producing single-layer graphene electrodes for molecular electronics at a large scale. Additionally, from Raman spectroscopy and electroburning carried out simultaneously, we can follow the heating process and infer the temperature at which the gap formation happens.

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confidence: 99%

High-yield fabrication of nm-size gaps in monolayer CVD graphene

et al. 2014

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“…It should be noted that in these junction models, the polyacene anchoring groups are assumed to bind above the zigzag edges of the graphene electrodes and thus the edge state and spin polarization at the zigzag edge will affect the junction transport properties. 40,41 For example, the transmission peaks appearing at about −57 meV below the Fermi level shown in Figures 4(b)-4(d) are mainly contributed by the edge state at the zigzag edge. This can be seen clearly from the local density of states (LDOS) of the carbon atoms at the zigzag edge (see Fig.…”

Section: A Linear Polyacenes As the Anchoring Groupmentioning

confidence: 95%

First-principles investigation on the electronic efficiency and binding energy of the contacts formed by graphene and poly-aromatic hydrocarbon anchoring groups

Wang

et al. 2015

The Journal of Chemical Physics

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The electronic efficiency and binding energy of contacts formed between graphene electrodes and poly-aromatic hydrocarbon (PAH) anchoring groups have been investigated by the non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that PAH molecules always bind in the interior and at the edge of graphene in the AB stacking manner, and that the binding energy increases following the increase of the number of carbon and hydrogen atoms constituting the PAH molecule. When we move to analyzing the electronic transport properties of molecular junctions with a six-carbon alkyne chain as the central molecule, the electronic efficiency of the graphene-PAH contacts is found to depend on the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the corresponding PAH anchoring group, rather than its size. To be specific, the smaller is the HOMO-LUMO gap of the PAH anchoring group, the higher is the electronic efficiency of the graphene-PAH contact. Although the HOMO-LUMO gap of a PAH molecule depends on its specific configuration, PAH molecules with similar atomic structures show a decreasing trend for their HOMO-LUMO gap as the number of fused benzene rings increases. Therefore, graphene-conjugated molecule-graphene junctions with high-binding and high-conducting graphene-PAH contacts can be realized by choosing appropriate PAH anchor groups with a large area and a small HOMO-LUMO gap.

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“…Finally, the possibility to exploit specific functionalizations to attach the molecular units to the graphene electrodes through carbon bonds and/or π-stacking seems to be a promising route to develop well-defined and robust junction configurations. In addition to these advantages, several theoretical papers have investigated the possibility to use graphene as an electrode to contact individual molecules [11][12][13][14][15][16], predicting interesting specific features such as quantum coherent transport [11], edge effects [13], and suppression of conductance fluctuations [14].…”

Section: Introductionmentioning

confidence: 99%