  We present electronic transport measurements on etched graphene nanoribbons
on silicon dioxide before and after a short hydrouoric acid (HF) treatment. We
report on changes in the transport properties, in particular, in terms of a
decreasing transport gap and a reduced doping level after HF dipping.
Interestingly, the effective energy gap is nearly unaffected by the HF
treatment. Additional measurements on a graphene nanoribbon with lateral
graphene gates support strong indications that the HF significantly modifies
the edges of the investigated nanoribbons leading to a significantly reduced
disorder potential in these graphene nanostructures.
