By comparing the 𝜀-𝑛 plots in Fig. with the dose-dependent intensity ratios (especially ID/IG) in Figs. and, a clearer picture emerges with regards to the e-beam chemistry process in graphene. For electron doses up to ~5000 µC/cm 2 in CVD graphene, we observed a monotonic increase in ID/IG (Figs. and) along with an increase in tensile strain in the graphene lattice (Fig. ). Within this dosage range, the hole concentration remained the same (𝑛 ~ 0.2 x 10 13 cm 2 ), implying the increase in D peak intensity is solely related to strain. We have previously shown that the incorporation of epoxide defects causes an out-of-plane displacement of ~28 pm for the carbon atoms bonded to the oxygen. This is accompanied by a stretching of the C-C bonds around that site. The out-of-plane sp -like defect and the C-C bond stretching could therefore explain the increasing D peak intensity and the strain observed with increasing dose up to ~5000 µC/cm 2 . At higher doses, and with presumably increasing functionalization, we see a stronger effect of the charge depletion in graphene leading to greater hole doping.