Figure 3
From: Charge transfer and electronic doping in nitrogen-doped graphene
(a) Representative STS spectra taken on each sample (the corresponding c is given below each curve). The position of the Dirac point is marked by a vertical line. The curves were shifted vertically for clarity. The horizontal lines mark the position dI/dV = 0. (b) 12 × 12 nm2 topographic image obtained with U = 1 V and I = 100 pA (on the sample for which c = 0.20% and μ(= EF − ED) = 190 meV, measured by ARPES). (c) μ(= EF − ED) mapping (performed in the same area as in b) showing its spatial variation. Black spots mark the points where no value could be extracted (no local minimum). (d) Corresponding map of the curvature of the dI/dV fits at the local minimum.
