Epitaxial Graphene Formation on SiC(000$\bar {1})$

The formation of epitaxial graphene on SiC(000$\bar {1})$ (the \textit{C-face}) is studied using atomic force microscopy, spatially resolved Auger electron spectroscopy, low energy electron diffraction, Raman spectroscopy, and electrical measurements. Starting from hydrogen-etched surfaces, graphene formation by vacuum annealing is observed over the temperature range 1200-1400\r{ }C. Unlike the situation for the Si-face, it is found for the C-face that the initial graphene formation is three-dimensional. Micron-size islands with height of several nm are formed, with the graphene being \underline {thinner} on these islands than between the islands. At higher formation temperatures the graphene layer becomes relatively flat, and has typical thickness of $>$10 monolayers. Electron diffraction indicates rotational disorder, with $\pm $15\r{ }-oriented spots observed in addition to the known $\pm $2.2\r{ }-spots.$^{2}$ Field-effect mobilities as high as 4400 cm$^{2}$/Vs for multi-layer graphene films are found, with relatively good homogeneity over the wafer. $^{2}$J. Hass et al., Phys. Rev. Lett. 100, 125504 (2008).