Introduction to Graphene Nanoribbon
By: Hatef Sadeghi
Graphene, a honeycomb sheet of carbon atoms in benzene ring structure [1-3] is likely to be replace by silicon base devices, not only because silicon based technology approaches its performance limitation in atomic sizes  but also because of its interesting and remarkable electronic, optical and thermal properties . From the discovery of monolayer graphene (GNR) in 2004  different aspects of the electronics properties of mono- bi- and tri- layer graphene leads Scientists to future investigations to find out differences between them. Further investigation shows that single atomic layer of carbon (GNR), has linear dispersion as reported in [7, 8]. Conduction and valance band meet each other in k Brillion zone of E-k relation plot in GNRs . So GNRs with zigzag shaped edge are metallic and GNRs with armchair shaped edges depending on their widths can be either metallic or semiconducting . One of the remarkable properties of BGN is the tunable energy band gap along applied perpendicular electric fields . Past studies show that conduction and valance bands in BGNs can be tuned by external electric field. On the other hand, the BGNs could be employed in digital electronics because band can be varied by means of an external perpendicular field and induced significant band gap between the valence and conduction bands from a zero-gap semiconductor to an insulator [5, 11-13]. Different behavior may also be expected for BGNs due to the presence of a gap in the energy spectrum of the latter material . However, high speed moving of charge carriers and losing relatively little energy to scattering, or colliding in graphene should lead to build ultrahigh frequency devices so-called ballistic transistors.
Andre Geim's Graphene introduction and research update lecture
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Groups working on Graphene
General knowledge in Graphene Nanoribbon from Wikipedia
The carbon-carbon bond length in graphene is about 0.142 nanometers. Graphene sheets stack to form graphite with an interplanar spacing of 0.335 nm, which means that a stack of 3 million sheets would be only one millimeter thick. Graphene is the basic structural element of some carbon allotropes including graphite, charcoal, carbon nanotubes and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons. The Nobel Prize in Physics for 2010 was awarded to Andre Geim and Konstantin Novoselov "for groundbreaking experiments regarding the two-dimensional material graphene".
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