Figure 4: Electrical measurements after doping and possible modifications of the energy band diagram.
From: Hot carrier multiplication on graphene/TiO2 Schottky nanodiodes

(a) Current–voltage curves after doping. (b) Change in Schottky barrier height dependent on doping. Illustrations of internal photoemission after impact ionization dependent on modification of the Schottky barrier in (c) the TETA-doped graphene/TiO2 and (d) the HNO3-doped graphene/TiO2 Schottky diode.