Graphene

A single sheet of atoms organized in a two-dimensional hexagonal crystal nanostructure makes up the carbon allotrope known as graphene, which is used in nanotechnology. The term originates from "graphite" and the prefix "-ene," which emphasizes the abundance of double bonds in the carbon allotrope seen in graphite. Every atom in a graphene sheet forms a strong -bond with its three closest neighbours and contributes one electron to a valence band that covers the whole sheet. This kind of bonding is also present in glassy carbon, fullerenes, polycyclic aromatic hydrocarbons, and (to a lesser extent) carbon nanotubes. Since the conduction band touches the valence band, graphene is a semimetal with peculiar electrical characteristics that are best explained by theories for massless quantum particles. The energy-to-momentum relationship of charge carriers in graphene is linear rather than quadratic, and the material may be used to create field-effect transistors with bipolar conduction. Long-range charge transport is ballistic, and the material displays substantial quantum oscillations as well as substantial and nonlinear diamagnetism. Along its plane, graphene transmits electricity and heat very effectively. The material's significant absorption of light at all visible wavelengths accounts for graphite's dark hue, yet despite its extraordinary thinness, a single sheet of graphene is practically transparent. The substance is approximately 100 times stronger than the strongest steel of the same thickness.