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Graphene (/ ˈ ɡ r æ f iː n /) [1] is a carbon allotrope consisting of a single layer of atoms arranged in a honeycomb planar nanostructure. [2] [3] The name "graphene" is derived from "graphite" and the suffix -ene, indicating the presence of double bonds within the carbon structure.
The electronic properties of graphene are significantly influenced by the supporting substrate. [59] [60] The Si(100)/H surface does not perturb graphene's electronic properties, whereas the interaction between it and the clean Si(100) surface changes its electronic states significantly. This effect results from the covalent bonding between C ...
Graphene oxide flakes in polymers display enhanced photo-conducting properties. [10] Graphene is normally hydrophobic and impermeable to all gases and liquids (vacuum-tight). However, when formed into graphene oxide-based capillary membrane, both liquid water and water vapor flow through as quickly as if the membrane was not present. [11]
Graphane is a two-dimensional polymer of carbon and hydrogen with the formula unit (CH) n where n is large. [1] Partial hydrogenation results in hydrogenated graphene, which was reported by Elias et al. in 2009 by a TEM study to be "direct evidence for a new graphene-based derivative". The authors viewed the panorama as "a whole range of new ...
The optical conductivity of graphene for visible frequencies is theoretically given by π / 4 G 0, and as a result its light absorption and transmission properties can be expressed in terms of the fine-structure constant alone. [19]
This factor is usually in the range 0.01 to 10, but can be lower or higher—for example, reaching 1,000 in exotic heavy fermion materials, or anywhere from zero to infinity (depending on definition) in graphene. As it simplifies the more general band theory, the electronic effective mass can be seen as an important basic parameter that ...
A prominent example of an intercalation compound is potassium graphite, denoted by the formula KC 8. Some graphite intercalation compounds are superconductors . The highest transition temperature (by June 2009) T c = 11.5 K is achieved in CaC 6 , and it further increases under applied pressure (15.1 K at 8 GPa). [ 65 ]
This "epitaxial graphene" consists of a single-atom-thick hexagonal lattice of sp 2-bonded carbon atoms, as in free-standing graphene. However, significant charge transfers from the substrate to the epitaxial graphene, and in some cases, the d-orbitals of the substrate atoms hybridize with the π orbitals of graphene, which significantly alters ...