  The electronic and transport properties of hybrid armchair zigzag
nanostructures including U-shaped graphene nanoribbons and patterned nanopores
structured graphene were studied using combination of density functional theory
and non-equilibrium Green function method. The density of state, electron
transmission spectra, and molecular orbitals were analyzed. The obtained
results show that GNRs junctions tend to open an energy gap when U-shaped
structures were formed due to the formation of quasi-bound states at zigzag
edges. The size of U shaped structures has enormous influences on the electron
transport of the system. We also considered the effect of corner form of the
U-shaped GNRs junctions on energy gap opening. It was found that as some carbon
atoms are add to the inner corner, the energy gap in U shaped GNRs
significantly changed. For patterned nanopores structured graphene, the
calculated results show that patterned nanopores enormous influence on
electronic and the transport properties though the GNRs junctions, depending on
the shape, size, and the number of nanopores. The study suggests that designed
tailored graphene systems based on hybrid armchair zigzag nanostructures can be
used to control the energy gap of graphene.
