A comparison of electronic transport properties of graphene with hexagonal boron nitride substrate and graphane, a first principle study

In this paper, a first-principle investigation of the electronic properties of graphene on hexagonal boron nitride substrate, and of one-sided and two-sided fully saturated hydrocarbons with C-H formula derived from a single sheet of graphene, tablelike and chairlike graphane, are presented within density functional theory (DFT). We obtain the most stable orientation of graphene on the substrate, the adsorption energy, the charge transfer and density of states (DOS) for these systems. We discuss the changes in the density of states as well as the extent of charge transfer, band gap and finally quantum conductivity and current for graphene due to the presence of the substrate and H atoms. We show that the band gap of 64 meV induced by the BN substrate can greatly improve the electrical characteristics of graphene-based field effect transistors (FETs) and its on/off ratio and decreases the minimum conductance by a factor three. We identify that the substrate is acting as a donor for graphene layer and graphene is acting as an acceptor with respect to H atoms after saturation with hydrogen. We show that graphene on h-BN substrate has higher on/off ratio respect to pristine graphene and higher conductance respect to tablelike graphane. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2013