Hysteresis in the resistance of a graphene device induced by charge modulation in the substrate

We have fabricated graphene devices on lightly doped Si substrates and show that pronounced changes in resistance versus gate voltage, R(V(g)), characteristics of these devices at 77 K are induced by the variation in the charge distribution in substrate with both gate voltage and illumination. The R(V(g)) of the graphene devices in the dark shows remarkable changes as the carriers in the underlying substrate go through accumulation, depletion, and inversion regimes. We demonstrate the possibility of using a graphene device as an optical-latch. (C) 2010 American Institute of Physics. [doi:10.1063/1.3473815]