An extended defect in graphene as a metallic wire.

Department of Physics, University of South Florida, Tampa, FL 33620, USA.
Nature Nanotechnology (Impact Factor: 33.27). 03/2010; 5(5):326-9. DOI: 10.1038/nnano.2010.53
Source: PubMed

ABSTRACT Many proposed applications of graphene require the ability to tune its electronic structure at the nanoscale. Although charge transfer and field-effect doping can be applied to manipulate charge carrier concentrations, using them to achieve nanoscale control remains a challenge. An alternative approach is 'self-doping', in which extended defects are introduced into the graphene lattice. The controlled engineering of these defects represents a viable approach to creation and nanoscale control of one-dimensional charge distributions with widths of several atoms. However, the only experimentally realized extended defects so far have been the edges of graphene nanoribbons, which show dangling bonds that make them chemically unstable. Here, we report the realization of a one-dimensional topological defect in graphene, containing octagonal and pentagonal sp(2)-hybridized carbon rings embedded in a perfect graphene sheet. By doping the surrounding graphene lattice, the defect acts as a quasi-one-dimensional metallic wire. Such wires may form building blocks for atomic-scale, all-carbon electronics.


Available from: Matthias Batzill, Jun 15, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Transition metal dichalcogenides (TMDs) are being considered for making a variety of electronic and optoelectronic devices such as beyond complementary metal-oxide-semiconductor (CMOS) switches, light-emitting diodes, solar cells, as well as sensors among others. Molybdenum disulfide (MoS2) is the most studied of the TMDs in part because of the availability in the natural or geological form. The performance of most devices is strongly affected by the intrinsic defects in geological MoS2. Indeed, most sources of current transition metal dichalcogenides have defects, including many impurities. The variability in the electrical properties of MoS2 across the surface of the same crystal has been shown to be correlated with local variations in stoichiometry as well as metallic-like and structural defects. The presence of impurities has also been suggested to play a role in determining the Fermi level in MoS2. The main focus of this work is to highlight a number of intrinsic defects detected on natural, exfoliated MoS2 crystals from two different sources that have been often used in previous reports for device fabrication. We employed room temperature scanning tunneling microscopy (STM) and spectroscopy (STS), inductively coupled plasma mass spectrometry (ICPMS), as well as X-ray photoelectron spectroscopy (XPS) to study the pristine surface of MoS2(0001) immediately after exfoliation. ICPMS used to measure the concentration of impurity elements can in part explain the local contrast behavior observed in STM images. This work highlights that the high concentration of surface defects and impurity atoms may explain the variability observed in the electrical and physical characteristics of MoS2.
    ACS Applied Materials & Interfaces 05/2015; DOI:10.1021/acsami.5b01778 · 5.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We study several graphene systems containing octagonal defects. Such defects are usually accompanied by pairs of pentagonal rings, but in curved structures, as for example in oblique junctions between carbon nanotubes, they may appear alone. We show that all the considered octagonal defects localize states at Fermi energy. The calculations are performed within the π-electron tight binding approximation. The electron interaction effects are taken into account by means of the Hubbard model.
    IEEE NANO 2012 - 12th International Conference on Nanotechnology, Birmingham; 08/2012
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We study how graphene morphology is affected by lower-symmetry metal surfaces supporting it during synthesis. For the Ni(111) triangular surface we find different ground-state structures (hexagonal and Klein) of zigzag edges in different directions and predict from first principles the equilibrium and growth shapes of graphene islands to explain the diversity of experimentally observed shapes. Then we present experimental observations of shapes of graphene islands grown simultaneously on different crystallographic surfaces of Cu, and explain the origin of these shapes in the symmetry of respective Cu surfaces---(111), (110), (100)---using Monte Carlo simulations of growth. The insight straightforwardly generalizes to other substrates and 2D materials.
    Physical Review Letters 05/2014; 114(11). DOI:10.1103/PhysRevLett.114.115502 · 7.73 Impact Factor