In graphene, ∆𝐸 7 is directly linked to the carrier density with the relation 𝑛 = : ∆; < ℏ= < > /𝜋, where 𝑣 7 is the graphene Fermi velocity. Based on this relation, for a hole density of 0.2 x 10 13 cm 2 (for electron doses up to ~5000 µC/cm 2 , Fig. ) and a Fermi velocity of 1.2 x 10 6 m/s, the change in Fermi level is ~0.1 eV. Thus, for doses beyond 5000 µC/cm 2 , ∆𝐸 7 increases (Fermi level decreases due to increasing hold doping) and is accompanied by a sharpening of the G peak and lowering of the D peak intensity. The G peak intensity is largely unaffected by both electron and hole doping and as a result, ID/IG decreases for electron doses above 5000 µC/cm 2 .