Next, we investigated the role of beam energy (i.e. acceleration voltage) on the creation of defects. For these studies the graphene was exposed to electron doses up to 10 5 µC/cm 2 in order to test the limits of our system as well as for probing the amounts of strain and doping in the graphene, as discussed further below. For the sake of convenience, we only performed highdose studies for limited acceleration voltages since these experiments took a considerable amount of time (up to an hour for the highest dose ~10 5 µC/cm 2 ). The peak frequencies and widths at various beam energies (1 -6 kV) exhibited similar trends as the 1kV data shown in Fig. (the evolution of peak frequencies and widths with increasing dose for all the acceleration voltages are shown in Fig. ). Interestingly, the changes in both frequencies and widths diminished with increasing voltage, which can be seen clearly in the plot of ID/IG vs. dose in Fig. . Firstly, a maximum ID/IG ~3 was obtained with the lowest beam energy -1kV. We have previously modeled epoxide functionalization in graphene and the effect of epoxide concentration on ID/IG , and found a theoretical maximum of ~ 2.5 for ID/IG. This agrees well with the experimental data for graphene patterned with a 1kV beam with a maximum ID/IG of ~3. Interestingly, this maximum value decreased monotonically with increasing beam energy while still maintaining the roughly parabolic dependence on electron dose (Fig. ). The ID/IG and ID/IG exhibited similar trends, with their inflection points monotonically changing with beam energy (Figs. and). These trends suggest that the species produced through radiolysis change with increasing beam energy. Indeed, earlier reports comparing H2O radiolysis products produced through 60 Co gamma, proton, He, N, and Ne ions show peroxide and H2 formation increase with increasing radiolysis energy . It is possible that similar processes are at play in the generation of radiolysis products using e-beam chemistry. The characterization of the radiolysis products and their effect on the functionalization in graphene could be performed through a combination of temperature programmed desorption and nanoscale infrared spectroscopy, something that is beyond the scope of this paper and will be the focus of a future study.