  Chemical vapor deposition (CVD) on Cu foil is one of the most promising
methods to produce graphene samples despite of introducing numerous grain
boundaries into the perfect graphene lattice. A rich variety of GB structures
can be realized experimentally by controlling the parameters in the CVD method.
Grain boundaries contain non-hexagonal carbon rings (4,5,7,8 membered rings)
and vacancies in various ratios and arrangements. Using wave packet dynamic
(WPD) simulations and tight-binding electronic structure calculations, we have
studied the effect of the structure of GBs on the transport properties. Three
model GBs with increasing disorder were created in the computer: a periodic 5-7
GB, a "serpentine" GB, and a disordered GB containing 4,8 membered rings and
vacancies. It was found that for small energies (E=EF+-1eV) the transmission
decreases with increasing disorder. Four membered rings and vacancies are
identified as the principal scattering centres. Revealing the connection
between the properties of GBs and the CVD growth method may open new
opportunities in the graphene based nanoelectronics.
