Energy diagrams of G/n-Si and G/p-Si Schottky junctions upon light illumination. The energy diagrams of G/n-Si (a) and G/p-Si (b) Schottky junctions upon light illumination, respectively. ΦG/ΦSi and EF G/EF Si denote the work functions and Fermi energy levels of graphene/Si. χSi is the electron affinity of silicon. E
are the conduction band and valence band of silicon, respectively.