Towards Wafer-Size Graphene Layers by Atmospheric Pressure Graphitization of Silicon Carbide.

Thermal annealing of SiC produces graphene layers on an insulating substrate, but the material is highly inhomogeneous. It is now shown that an argon atmosphere during annealing improves uniformity of the graphene layers dramatically and yields better transport characteristics. This is a very important result for the development of graphene-based electronic devices. Graphene, a single monolayer of graphite, has recently attracted considerable interest owing to its novel magneto-transport properties1,2,3, high carrier mobility and ballistic transport up to room temperature4. It has the potential for technological applications as a successor of silicon in the post Moore’s law era5,6,7, as a single-molecule gas sensor8, in spintronics9,10,11, in quantum computing12 or as a terahertz oscillator13. For such applications, uniform ordered growth of graphene on an insulating substrate is necessary. The growth of graphene on insulating silicon carbide (SiC) surfaces by high-temperature annealing in vacuum was previously proposed to open a route for large-scale production of graphene-based devices5,6. However, vacuum decomposition of SiC yields graphene layers with small grains (30–200 nm; refs 14–16). Here, we show that the ex situ graphitization of Si-terminated SiC(0001) in an argon atmosphere of about 1 bar produces monolayer graphene films with much larger domain sizes than previously attainable. Raman spectroscopy and Hall measurements confirm the improved quality of the films thus obtained. High electronic mobilities were found, which reach μ=2,000 cm 2 V−1 s−1 at T=27 K. The new growth process introduced here establishes a method for the synthesis of graphene films on a technologically viable basis.