  Graphene nanoribbons (GNRs) based T junctions were designed and studied in
this paper. These junctions were made up of shoulders (zigzag GNRs) joined with
stems (armchair GNRs). We demonstrated the intrinsic transport properties and
effective boron (or nitrogen) doping of the junctions by using first principles
quantum transport simulation. Several interesting results were found: i) The
I-V characteristics of the pure-carbon T junctions were shown to obey Ohm law
and the electrical conductivity of the junction depends on the height of the
stem sensitively. ii) boron (or nitrogen) doping on the stems doesnt change the
Ohm law of the T junctions, but the result is opposite when doping process
occurs at the shoulders. This feature could make such quasi-2D T junction a
possible candidate for nanoscale junction devices in a 2D network of
nanoelectronic devices in which conducting pathways can be controlled.
