Electrical transport in graphene with different interface conditions

The effect of the interface on the electrical resistance of graphene chemically deposited from the gas phase (CVD graphene) has been studied in the range from room temperature to the nitrogen boiling temperature. The resistance of a single-layer CVD graphene in the cases of its contacting with Si/SiO$_2$ and GaAs substrates demonstrates a nearly linear metallic temperature dependence with almost the same slope of the normalized curves. This slope corresponds to an increase in the graphene resistance by $\sim$ 8% when graphene is heated from the boiling nitrogen temperature to room temperature. The four-layer graphene demonstrates a semiconducting temperature dependence in the same temperature range. It has been found that the sputtering of an organic insulator (parylene) on the four-layer graphene increases the slope of this dependence by $\sim$ 5% and, at room temperature, increases the graphene resistance by $\sim$ 20%.