  Controlled modification of graphene properties is essential for its proposed
electronic applications. Here we describe a possibility of tuning electrical
properties of graphene via electron beam irradiation. We show that by
controlling the irradiation dose one can change the carrier mobility and
increase the resistance at the minimum conduction point in the single layer
graphene. The bilayer graphene is less susceptible to the electron beam
irradiation. The modification of graphene properties via irradiation can be
monitored and quantified by the changes in the disorder D peak in Raman
spectrum of graphene. The obtained results may lead to a new method of defect
engineering of graphene physical properties, and to the procedure of "writing"
graphene circuits via e-beam irradiation. The results also have implications
for fabrication of graphene nanodevices, which involve scanning electron
microscopy and electron beam lithography.
