Figure 2: Charge transport data.
From: Homoepitaxial tunnel barriers with functionalized graphene-on-graphene for charge and spin transport
(a) Dirac curves taken using the SiO2/Si substrate as a back gate. Blue: between contacts 2 and 3 (only on the fluorographene). Black: between contacts 1 and 4 (only on the graphene channel). The fluorographene shows no Dirac point, indicating that it is fully insulating and electrically uncoupled from the graphene that is underneath it. (b) current-voltage curves for a typical device. Taken between contacts 1 and 2 or 1 and 3 (includes the tunnel barrier), the curves are non-Ohmic. Taken between contacts 1 and 4 (graphene channel only) the curve is linear. The inset further highlights this by showing dV/dI versus V when the tunnel barrier is included in the circuit. (c) Zero bias resistance versus temperature for the Py contacts showing a weak temperature dependence (non-metallic behaviour) that is a hallmark of a good tunnel barrier.
