We performed optical annealing experiments at the edges of nanopatterned graphene to study the resultant edge reconstruction. The lithographic patterning direction was orthogonal to a zigzag edge. μ-Raman spectroscopy shows an increase in the polarization contrast of the G band as a function of annealing time. Furthermore, transport measurements reveal a 50% increase of the GNR energy gap after...

Vibrational properties of graphene nanoribbons are examined with density functional based tight-binding method and non-resonant bond polarization theory. We show that the recently discovered reconstructed zigzag edge can be identified from the emergence of high-energy vibrational mode due to strong triple bonds at the edges. This mode is visible also in the Raman spectrum. Total vibrational den...

Precise spatial control of materials is the key capability of engineering their optical, electronic, and mechanical properties. However, growth of graphene on Cu was revealed to be seed-induced two-dimensional (2D) growth, limiting the synthesis of complex graphene spatial structures. In this research, we report the growth of onion ring like three-dimensional (3D) graphene structures, which are...

We investigate the Josephson effect in the graphene nanoribbons of length L smaller than the superconducting coherence length and an arbitrary width W . We find that in contrast to an ordinary superconducting quantum point contact (SQPC) the critical supercurrent Ic is not quantized for the nanoribbons with smooth and armchair edges. For a low concentration of the carriers Ic decreases monotoni...

Stimulated by recent advances in isolating graphene and similarities to single-wall carbon nanotubes, simulations were performed to assess the effects of static disorder on the conductance of metallic armchair- and zigzag-edge graphene nanostrips. Both strip types were found to have outstanding ballistic transport properties in the presence of a substrate-induced disorder. However, only the zig...

The energy of an arbitrary graphene edge, from armchair (A) to zigzag (Z) orientation, is derived in analytical form. It contains a "chemical phase shift" determined by the chemical conditions at the edge. Direct atomistic computations support the universal nature of the relationship, definitive for graphene formation, and shapes of the voids or ribbons. It has further profound implications for...

We study the band and transport features of zigzag graphene nanoribbon with an antidot lattice. It is found that an antidot lattice could turn semi-metal graphene into a semiconductor. The size of the band gap can be tuned by the position of the antidots and the distance D between the two nearest antidots. For a finite superlattice with N antidots and a large D, a group of (N - 1) splitting res...

We show that edge stresses introduce intrinsic ripples in freestanding graphene sheets even in the absence of any thermal effects. Compressive edge stresses along zigzag and armchair edges of the sheet cause out-of-plane warping to attain several degenerate mode shapes. Based on elastic plate theory, we identify scaling laws for the amplitude and penetration depth of edge ripples as a function ...