Ultrahigh mobility semiconducting epitaxial graphene on silicon carbide

Abstract

Epigraphene, which is graphene that is epitaxially grown on a single crystal silicon carbide (SiC) substrate, was proposed as a path to extend Moore’s roadmap beyond silicon at the beginning of the millennium. Despite considerable progress, the lack of a bandgap in graphene and steps on the substrate continued to be roadblocks. Here we show a new method to produce millimeter scale step-free terraces covered with a graphene-like interface that is bonded to the SiC surface. This so-called buffer layer is found to be two-dimensional semiconducting epigraphene (SEG) with a 0.6 eV bandgap and a room temperature mobility exceeding 4000 cm2V-1s-1, which surpasses all current 2D single layer semiconductors by a factor of 10. A top-gated SEG field-effect transistor demonstrates an on-to-off ratio of 104 which is suitable for digital electronics. In addition, we also find that hydrogen intercalation converts SEG into a high-mobility semi-metallic epigraphene monolayer that can be seamlessly integrated with SEG. Centimeter scale mean free paths are observed in the epigraphene edge state of this quasi-freestanding monolayer, which is by a factor of 1000, the largest room temperature electronic mean free path observed in any material.

Silicene Applications in Nanotechnology: From Transistors to Bendable Membranes

“…Hence, it is possible to leverage on the Xenes properties to artificially create the best candidate for the specific target applications. A synergistic cooperation between theory and experiments is here necessary to drive research towards the most promising configuration regarding Xenes on substrates, as recently occurred even for the forerunner graphene whose lack of bandgap has been eventually surmounted [86]. Although such a Xenes engineering is the desired outcome, it should be pointed out that even integrating Xenes in the silicon-based ICs could be a viable option to perform secondary tasks (e.g., heat dissipation) or boosting performance of the overall systems [82].…”