Graphene-Silicon Hybrid Drift Device

This work reports the photo-charge transport and multiplication in a hybrid heterostructure, combining MOS and the Schottky junctions based on graphene and silicon. We observed that the deep depletion state in the graphene-oxide-semiconductor (GOS) region induces internal gating on the graphene/silicon (Gr/Si) Schottky junction. A strong surface potential in the deep depletion region of GOS creates a carrier multiplication path in an out-of-plane direction to the Si/SiO
2
interface. The inversion region formed near Si/SiO
2
interface provides a low resistance path for the in-plane charge transport. At appropriate bias differences between GOS and Schottky regions, carriers experience an additional avalanche effect at the transition region in the in-plane geometry. As a result of these two carrier multiplication effects in the charge transport paths of the hybrid device, we observed a large external quantum efficiency (1042%). The dynamic photoresponse of the hybrid device shows a linearity of 99.85%, with the slope directly reflecting the generation rate and electric field strength in the internal gating region. This hybrid Gr-Si heterostructure operates in the same fashion as the continuous drift version of the discrete silicon drift device, with potential applications in position-sensing and weak light detection.