Plasmon-Induced Doping of Graphene

A metallic nanoantenna, under resonant illumination, injects nonequilibrium hot electrons into a nearby graphene structure, effectively doping the material. A prominent change in carrier density was observed for a plasmonic antenna-patterned graphene sheet following laser excitation, shifting the Dirac point, as determined from the gate-controlled transport characteristic. The effect is due to hot electron generation resulting from the decay of the nanoantenna plasmon following resonant excitation. The effect is highly tunable, depending on the resonant frequency of the plasmonic antenna, as well as on the incident laser power. Hot electron-doped graphene represents a new type of hybrid material that shows great promise for optoelectronic device applications.