Roberto Grassi

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Recent experiments show that a substantial energy gap in graphene can be induced via patterned hydrogenation on an iridium substrate. Here, we show that the energy gap is roughly proportional to N(H)(1/2)/N(C) when disorder is accounted for, where N(H) and N(C) denote concentrations of hydrogen and carbon atoms, respectively. The dispersion relation,(More)
—In this paper, we clarify the physical mechanism for the phenomenon of negative output differential resistance (NDR) in short-channel graphene FETs through nonequilibrium Green's function simulations and a simpler semianalytical ballistic model that captures the essential physics. This NDR phenomenon is due to a transport mode bottleneck effect induced by(More)
—A mode space tight-binding approach for the simulation of armchair graphene nanoribbon FETs is discussed. It makes use of slab-dependent modes and a novel criterion for mode selection going beyond the one based on the lowest energy subbands. For ideal ribbons we show that, by splitting the modes into decoupled groups, the new method provides results almost(More)
* We would like to thank Bocconi University for granting access to its administrative archives for this project. In particular, the following persons provided invaluable and generous help: their precious comments. We would also like to thank seminar participants at Bocconi University. The views expressed in this paper are solely those of the authors and do(More)
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