  Based on first-principles calculations, electronic properties of
edge-functionalized zigzag graphene nanoribbons (ZGNRs) on SiO2 substrate are
presented. Metallic or semiconducting properties of ZGNRs are revealed due to
various interactions between edge-hydrogenated ZGNRs and different SiO2 (0001)
surfaces. Bivalent functional groups decorating ZGNRs serve as the bridge
between active edges of ZGNRs and SiO2. These functional groups stabilize ZGNRs
on substrate, as well as modify the edge states of ZGNRs and further affect
their electronic properties. Band gaps are opened owing to edge states
destruction and distorted lattice in ZGNRs.
