Growth of graphene on 3C-SiC nanostructures by UHV annealing

Full text: There is a growing body of literature that recognizes the potential of graphene for use in electronics. However, the fact that graphene is a semimetal with zero bandgap is a key issue which challenges its remarkable range of applications. Therefore, over the past few years, a considerable literature has grown up around the theme of producing a semiconducting graphene. Thermal decomposition of SiC has proven to be an excellent method to grow transfer-free wafer-scale graphene. Theoretical work suggests that a bandgap might be opened in graphene through quantum confinement, for example in graphene nanoribbons. In this research we attempt to manipulate the SiC substrate dimension to grow graphene over small nanostructures with lateral sizes ranging from tens of nm to 1 µm. To date, there has been no report about the growth of graphene on nanometer-scale SiC mesas, and very little is known about the effect of changing the dimension and characteristic of the substrate on which graphene is grown. In order to elucidate the possibility for patterned graphene-growth in substrate-defined geometries, we have examined the effect of SiC patterning on graphene growth. SiC mesas have been fabricated by patterning SiC/Si substrates using Focused Ion Beam (FIB) milling using X-ray photoelectron spectroscopy (XPS), scanning tunnelling microscopy (STM), scanning electron microscopy (SEM), helium ion microscopy (HIM) and Raman spectroscopy were used to investigate the surface condition and to identify surface reconstructions produced during growth. Our results indicate that without employing preventative measures, FIB milling leads to beam-related damage that prevents graphene growth on the SiC/Si milled structures. However, using a modified procedure, we succeeded to produce epitaxial graphene over the SiC nanostructures patterned by FIB. (author)