Is graphene more conductive than h-BN?

Electronic tunneling through multilayers of graphene and h-BN sandwiched between gold electrodes is investigated by density functional theory together with the non-equilibrium Green's Function method. The calculated results predict similar transmittance characteristics for the device configuration consisted of graphene and h-BN monolayers, though the pristine graphene and h-BN layers are semimetal and semiconductor, respectively. The h-BN monolayer exhibits a higher degree of p-type doping due to electron transfer from boron to the contact gold atoms relative to that predicted for graphene. A strong coupling of electrode-monolayer at the device interface is therefore likely to be the cause of similar vertical electron tunneling characteristics of the device configurations considered. For the multilayer cases, h-BN shows an exponential dependency of transmission function on the number of layers, whereas multilayer graphene exhibits relatively high tunneling probability due to a stronger interlayer coupling between adjacent layers of graphene.