Gap control via graphene solid-state reactions

While a gapless dispersion law of Dirac fermions in graphene does warrant admiration, to serve as useful semiconductor graphene needs a gap. Relatively inert, it can nevertheless be induced to react. A generic outcome of a reaction, C + A -$>$ C$_{1-x}$A$_{x}$ is a transition of some C-atoms from their sp$^ {2}$- into sp$^{3}$-state, corresponding to a situation of the insulating, ultimate (mono- or few-layer) diamond slab [1]. Computations support a concept that the product of such reactions (A = H, F, O, Cl, etc.) forms a well-defined phase [2], permitting a patterning of 2D-geometries with useful properties: interconnects-nanoroads [3], quantum isles-dots [4], etc. Comparison of hydrogenation (A = H) into graphAne with fluorination (A = F) into 2D-teflon, shows the former as hindered by nucleation barrier and reversible (H-storage), in contrast to barrier-less reaction into a stable CF in the latter. *** In collaboration with F. Ding, E. Penev, M.A. Ribas, and A.K. Singh. ***\\[4pt] [1] E. Munoz, et al., Diamond \& Related Mater., 19, 368, 2010.\\[0pt] [2] Y. Lin, et al., Phys. Rev. B, 78, 041402(R), 2008.\\[0pt] [3] A.K. Singh and BIY, Nano Lett., 9, 1540, 2009.\\[0pt] [4] A.K. Singh, et al., ACS Nano, 4, 3510, 2010.\\[0pt] [5] ``Patterning on fluorinated graphene,'' M. Ribas, et al., Nano Res. (2010).