  Substituting heteroatoms and non-benzenoid carbons into nanographene
structure offers an unique opportunity for atomic engineering of electronic
properties. Here we show the bottom-up synthesis of graphene nanoribbons (GNRs)
with embedded fused BN-doped rubicene components on a Au(111) surface using
on-surface chemistry. Structural and electronic properties of the BN-GNRs are
characterized by scanning tunneling microscopy (STM) and atomic force
microscopy (AFM) with CO-terminated tips supported by numerical calculations.
The periodic incorporation of BN heteroatoms in the GNR leads to an increase of
the electronic band gap as compared to its undoped counterpart. This opens
avenues for the rational design of semiconducting GNRs with optoelectronic
properties.
