Figure 2 shows the results reported in Reference  for a device based on a 20-nm-long graphene ribbon with a boron concentration equal to 0.3% and 0.6%, compared with those achieved for the undoped graphene ribbon. The boron concentration was defined as the ratio between the number of substitutional boron atoms and the total number of atoms within the channel. Numerical convergence problems precluded the simulation of ribbons with boron percentages larger than 0.6%. For each boron concentration, the dashed thin lines represent the characteristics obtained for the different random distributions of dopants, while the thick solid lines correspond to their average. When increasing the boron concentration, the hole and electron branches of the ID(VGS) characteristic become more asymmetric, the voltage range for which we have low conduction through the device (and thus the mobility gap) widens, and the ION/IOFF ratio increases.