Graphene films grown on Si substrate via direct deposition of solid-state carbon atoms

Graphene films were grown on Si(1 1 1) substrates at different temperatures (600, 700 and 800 °C) by directly depositing solid-state carbon atoms through solid-state molecular beam epitaxy (SSMBE). The structural properties were characterized by reflection high energy electron diffraction (RHEED), Raman spectroscopy and near-edge X-ray absorption fine-structure (NEXAFS). The results showed that SiC precipitates primarily formed at 700 and 800 °C, as a small quantity of carbon atoms were deposited. When carbon atoms continued depositing, graphene films formed at 800 °C and amorphous or polycrystalline carbon thin films formed at 700 and 600 °C. We think that graphene films could be grown on Si(1 1 1) substrates because of the high activity of carbon atoms at 800 °C and weak interaction between carbon atoms and silicon atoms of substrate due to a SiC buffer layer stabilizing the surface of Si substrate.