Fabrication and electrical characterization of exfoliated graphene based devices

We report on the fabrication of graphene based devices using the micromechanical exfoliation of natural graphite and their electrical characterization including metallic contact resistance measurements, mobility and density charge carriers measurements. The first and major application aimed is the quantrum Hall effect (QHE) metrology. The samples fabricated, from both monolayer and bilayer graphene flakes, with rather low contact resistance (typically a few tens or hundreds of Ω) enable the performance of QHE quantization tests exact within uncertainties of some part in 10⁷. The limitations of this record accuracy are suggested by the results of the extensive characterizations performed (small size samples (<;100 μm²), poor charge carrier density homogeneity, irreproducibility and instability of the contacts). The results obtained could be very usefull for other applications based on graphene transport properties.