We report on magneto-transport measurements on low-density, large-area monolayer epitaxial graphene devices grown on SiC. We observe temperature (T)-independent crossing points in the longitudinal resistivity ρxx, which are signatures of the insulator-quantum Hall (I-QH) transition, in all three devices. Upon converting the raw data into longitudinal and Hall conductivities σxx and σxy, in the ...

Ordered graphene has been extensively studied. In this paper, we undertake a density functional study of topologically disordered analogs of graphene, in the formof a random network, consisting predominantly of hexagonal rings, but also including pentagons and heptagons. After some preliminaries with crystalline material, we relax various random network models and find that the presence of carb...

Large area thin films of few-layered unfunctionalized graphene platelets are developed with fine control over the thickness. The thin films are obtained by a Langmuir-Blodgett assembly at the interface of graphene solution in N-methyl-2-pyrrolidone (NMP) and water, and their optoelectronic properties and conduction mechanism are investigated in relation to lateral flake size and thin film thick...

The ability to engineer a thin two-dimensional surface for light trapping across an ultra-broad spectral range is central for an increasing number of applications including energy, optoelectronics, and spectroscopy. Although broadband light trapping has been obtained in tall structures of carbon nanotubes with millimeter-tall dimensions, obtaining such broadband light-trapping behavior from nan...

The dynamics of an electron's wave packet on hydrogenated graphene at low hydrogen coverages has been simulated using the tight-binding model. It is found that the bonding between the hydrogen and carbon atoms induces an impurity electron state at an energy of ≈ 0.14 eV above the Dirac crossing energy ED, at which the impurity's scattering of electrons is resonantly enhanced. The asymmetry foun...

Based on the recently developed picture of an electronic ideal relativistic fluid at the Dirac point, we present an analytical model for the conductivity in graphene that is able to describe the linear dependence on the carrier density and the existence of a minimum conductivity. The model treats impurities as submerged rigid obstacles, forming a disordered medium through which graphene electro...

We calculate the mode-dependent transmission probability of massless Dirac fermions through an ideal strip of graphene (length L, width W, no impurities or defects) to obtain the conductance and shot noise as a function of Fermi energy. We find that the minimum conductivity of order e2/h at the Dirac point (when the electron and hole excitations are degenerate) is associated with a maximum of t...

We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tightbinding model. First, we consider the magnetoconductance of such rings and observe the Aharonov-Bohm effect. We investigate different regimes of the magnetic flux up to the quantum Hall regime, where the Aharonov-Bohm oscillations are suppres...