Confocal Raman spectroscopy is used to study the phonon modes of mechanically exfoliated single-layer graphene sheets in ambient air. We observe that ambient gas induces obvious shifts in the G band frequency as well as the change in intensity ratio of 2D and G bands, I(2D)/I(G), owing to the Fermi energy change by ambient gas doping. The change in I(2D)/I(G) for the armchair edge is significan...

We review recent studies of coherent phonons (CPs) corresponding to the radial breathing mode (RBM) and G-mode in single-wall carbon nanotubes (SWCNTs) and graphene. Because of the bandgap-diameter relationship, RBM-CPs cause bandgap oscillations in SWCNTs, modulating interband transitions at terahertz frequencies. Interband resonances enhance CP signals, allowing for chirality determination. U...

We report the pH response enhancement of the electrolyte-gated graphene field effect transistors by controllably introducing edge defects. An average improvement of pH response from 4.2 to 24.6 mV/pH has been observed after downscaling the pristine graphene into graphene nanoribbon arrays with electron beam lithography (EBL) and oxygen plasma. We attribute the improved pH response in graphene n...

In graphene edges or nanographene, the presence of edges strongly affects the electronic structure depending on their edge shape (zigzag and armchair edges) as observed with the electron wave interference and the creation of non-bonding π -electron state (edge state). We investigate the edge-inherent electronic features and the magnetic properties of edge-sate spins in nanographene/graphene edg...

We report on the experimental demonstration and electrical characterization of N = 7 armchair graphene nanoribbon (7-AGNR) field effect transistors. The back-gated transistors are fabricated from atomically precise and highly aligned 7-AGNRs, synthesized with a bottom-up approach. The large area transfer process holds the promise of scalable device fabrication with atomically precise nanoribbon...

We have used classical molecular dynamics based on the Brenner potential describing carbon-carbon covalent bonds to study the melting point and vacancy movement in a rectangular graphene nanoribbon. The melting point of the graphene nanoribbon extracted from the numerical simulation is ~3400 K. We also found that two separated vacancies at high temperature (e.g., ~3000 K, below the melting poin...

Based on atomistic simulations, the nonlinear elastic properties of monolayer graphene nanoribbons under quasistatic uniaxial tension are predicted, emphasizing the effect of edge structures (armchair and zigzag, without and with hydrogen passivation). The results of atomistic simulations are interpreted using a theoretical model of thermodynamics, which enables determination of the nonlinear f...

Superior electronic properties of graphene make it a substitute candidate for beyond-CMOSnanoelectronics in electronic devices such as the field-effect transistors (FETs), tunnel barriers, andquantum dots. The armchair-edge graphene nanoribbons (AGNRs), which have semiconductor behavior,are used to design the digital circuits. This paper presents a new design of ternary half a...

Qiang Lu and Rui Huang Department of Aerospace Engineering and Engineering Mechanics, University of Texas, Austin, Texas 78712, USA ABSTRACT Based on atomistic simulations, the nonlinear elastic properties of monolayer graphene nanoribbons under quasistatic uniaxial tension are predicted, emphasizing the effect of edge structures (armchair and zigzag, without and with hydrogen passivation). T...