Graphene-metal contact resistivity on semi-insulating 6H-SiC(0001) measured with Kelvin probe force microscopy

We present Kelvin probe force microscopy measurements and resistance network simulations of the lateral charge transport across few-layer graphene on the semi-insulating 6H-SiC(0001) surface. After preparation of the SiC crystal by thermal decomposition, gold electrodes were prepared on the top of the graphene layers. The transport field is extracted by subtracting measurements of reverse lateral bias applied to the gold electrodes. Graphene sheet resistances as low as 0.75 kΩ/sq were observed. By comparing the experimental transport measurements with a resistance network simulation the contact resistivity between graphene and a gold electrode can be determined to be <1×10−6 Ω cm2.