Spatial variation of the number of graphene layers formed on the scratched 6H-SiC(0001) surface

The unique properties of graphene can vary greatly depending on the number of graphene layers; therefore, spatial control of graphene thickness is desired to fully exploit these properties in promising new devices. Using low energy electron microscopy (LEEM), we investigate how scratches on the surface of 6H-SiC(0 0 0 1) affect the epitaxial growth of graphene. Oscillations in the LEEM-image intensity as a function of electron energy (I-V LEEM analysis) show that the number of graphene layers clearly differs between regions of scratched and smooth substrate. The extent of the thicker graphene layers formed above scratches is found to be significantly larger than the width of the scratch itself. This finding can be implemented as an additional technique for spatially modulating graphene thickness. (C) 2012 Elsevier B.V. All rights reserved.