Direct growth of wafer-scale highly oriented graphene on sapphire.

Direct chemical vapor deposition (CVD) growth of wafer-scale high-quality graphene on dielectrics is of paramount importance for versatile applications. Nevertheless, the synthesized graphene is typically a polycrystalline film with high density of uncontrolled defects, resulting in a low carrier mobility and high sheet resistance. Here, we report the direct growth of highly oriented monolayer graphene films on sapphire wafers. Our growth strategy is achieved by designing an electromagnetic induction heating CVD operated at elevated temperature, where the high pyrolysis and migration barriers of carbon species are easily overcome. Meanwhile, the embryonic graphene domains are guided into good alignment by minimizing its configuration energy. The thus obtained graphene film accordingly manifests a markedly improved carrier mobility (~14,700 square centimeters per volt per second at 4 kelvin) and reduced sheet resistance (~587 ohms per square), which compare favorably with those from catalytic growth on polycrystalline metal foils and epitaxial growth on silicon carbide.