AVS 60th International Symposium and Exhibition
    Graphene and Other 2D Materials Focus Topic Tuesday Sessions
       Session GR+AS+NS+SP+SS-TuA

Paper GR+AS+NS+SP+SS-TuA1
Intercalation of SiC(0001) with Silicon

Tuesday, October 29, 2013, 2:00 pm, Room 104 B

Session: Characterization including Microscopy and Spectroscopy of 2D Materials
Presenter: S. Oida, IBM T.J. Watson Research Center
Authors: S. Oida, IBM T.J. Watson Research Center
J. Hannon, IBM T.J. Watson Research Center
R.M. Tromp, IBM T.J. Watson Research Center
Correspondent: Click to Email
Graphene growth on SiC is of interest, in part, because the synthesis takes place directly on an insulating substrate. Because of strong electronic coupling to the substrate, the first graphene layer (called the "buffer layer") does not have the unique electronic properties of graphene . The second layer has much weaker coupling to the substrate and exhibits the high carrier mobility associated with monolayer graphene. However, the synthesis of exactly two monolayers of graphene is difficult, and is usually accompanied by increased surface roughness. Therefore, it would be advantageous to electronically "decouple" the buffer layer and avoid the need to synthesize thicker layers. Here we show that by exposing a buffer layer surface to disilane in ultra-high vacuum it is possible to form Si-rich structures underneath the buffer layer domains. We do this by imaging the surface during disilane exposure using low-energy electron microscopy (LEEM). Furthermore, spatially-resolved electron-energy loss spectroscopy (EELS) shows that the intercalated Si strongly modifies the electronic coupling to the SiC substrate, effectively decoupling the graphene. Finally, we show that the intercalation is fully reversible. That is, with annealing in ultra-high vacuum, the intercalated silicon will desorb from the surface.