Fig. 2
Schottky emitter of the Si–Gr-Ge transistor. a A typical I–V characteristic of the top Si–Gr emitter junction at room temperature showing an obvious rectifying behavior. b Temperature-dependent characteristics of the current. An Arrhenius plot at a voltage of −0.1 V gives a Schottky barrier height of 0.64 eV at room temperature. c Comparison of the on-currents of graphene-base transistors with different emitters. The Si–Gr Schottky emitter shows a current of 692 A cm−2 at −5 V. d Comparison of fα of graphene-base transistors with different emitters. The one with the Si–Gr Schottky emitter shows the best cutoff frequency of 1.2 GHz
