  Graphene nanoribbons (GNRs) with widths down to 16 nm have been characterized
for their current-carrying capacity. It is found that GNRs exhibit an
impressive breakdown current density, on the order of 10^8 A/cm2. The breakdown
current density is found to have a reciprocal relationship to GNR resistivity
and the data fit points to Joule heating as the likely mechanism of breakdown.
The superior current-carrying capacity of GNRs will be valuable for their
application in on-chip electrical interconnects. The thermal conductivity of
sub-20 nm graphene ribbons is found to be more than 1000 W/m-K.
