Graphene

Column is two-dimensional crystal consisting of a single layer of carbon atoms collected in the hexagonal lattice. His theoretical research began long before the actual receipt of samples of material, because of the graph, you can collect three-dimensional crystal of graphite. Column is the base for building a theory of the crystal. Graphite is semimetals, and has been shown in 1947, P. Vollesom, the band structure of the graph as there is no forbidden zone, and at points of contact of valence band and the zone of the energy spectrum of conduction electrons and holes as a linear function of the wave vector. This type of spectrum are massless photons and ultrarelativistic particles and neutrinos. Therefore say that the effective mass of electrons and holes in grafene near ground zero area. But there's worth mentioning that, despite the similarity of photon and massless carriers in grafene there are some significant differences that make the media in grafene unique in its physical nature, namely: the electrons and holes are fermions, and they are charged. Currently equivalent to those of massless charged fermions of elementary particles is not known.

Despite these specific features, experimental confirmation of these findings have not been to the year 2005, since not been able to create a graph. Moreover, even before it has been proved theoretically that an ideal-free two-dimensional film can not be obtained due to instability on the winding-up or curling. Thermal fluctuations lead to melting of two-dimensional crystals at any finite temperature.

Interested in graphene emerged again after the discovery of carbon nanotubes, since all the original theory was based on simple models of nanotubes as scanning cylinder. Therefore, the theory for graphs in the annex to the nanotubes are well established.

Attempts to obtain the graph attached to other materials, began with experiments using a simple pencil, and continued with the use of atomic force microscope for the mechanical removal of layers of graphite, but have not achieved success. The use of graphite with the introduction of (intercalated graphite) in mezhploskostnoe space alien atoms (used to increase the distance between adjacent layers and their cleavage) also did not lead to a result.

In 2004, the Russian and British scientists has been published in the journal Science, which reported the receipt of a graph on the oxidized silicon substrate. Thus, stabilization of the two-dimensional film due to connection with a thin layer of SiO2 dielectric, similar to the thin films grown by using LATE. The first measured the conductivity, the effect of Shubnikov - de Haas, the Hall effect for samples consisting of carbon films with atomic thickness.