90 research outputs found
A Two-Dimensional Carbon Semiconductor
We show that patterned defects can be used to disrupt the sub-lattice
symmetry of graphene so as to open up a band gap. This way of modifying
graphene's electronic structure does not rely on external agencies, the
addition of new elements or special boundaries. The method is used to predict a
planar, low energy, graphene allotrope with a band gap of 1.2 eV. This defect
engineering also allows semiconducting ribbons of carbon to be fabricated
within graphene. Linear arrangements of defects lead to naturally embedded
ribbons of the semiconducting material in graphene, offering the prospect of
two-dimensional circuit logic composed entirely of carbon.Comment: 4 pages, 5 figure
Nano-Engineering Defect Structures on Graphene
We present a new way of nano-engineering graphene using defect domains. These
regions have ring structures that depart from the usual honeycomb lattice,
though each carbon atom still has three nearest neighbors. A set of stable
domain structures is identified using density functional theory (DFT),
including blisters, ridges, ribbons, and metacrystals. All such structures are
made solely out of carbon; the smallest encompasses just 16 atoms. Blisters,
ridges and metacrystals rise up out of the sheet, while ribbons remain flat. In
the vicinity of vacancies, the reaction barriers to formation are sufficiently
low that such defects could be synthesized through the thermally activated
restructuring of coalesced adatoms.Comment: 4 pages, 5 figure
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