In 1859, Benjamin Collins Brodie had already recognized that the structure of thermally reduced graphite oxide was lamellar. The structure of graphite was determined in 1916 by the related method of powder diffraction, and its structure was determined from single-crystal diffraction in 1924. In early 20^th century, the researchers observed the single layers of graphite by transmission electron microscopy. But graphene was first produced by Andre Geim and Konstantin Novoselov until 2004. They used a kind of special tape to peel the highly oriented pyrolytic graphite and finally got the graphene, the graphite slide which is only one atom thick.¹

Figure 1: the tape used to produce graphene                                                   Figure 2:  Andre Geim and Konstantin Novoselov in the meeting

Until now, there are about 9 methods to produce the graphene: Micromechanical cleavage, Anodic bonding, Photoexfoliation, Liquid phase exfoliation, Growth on SiC, Precipitation from metal, Chemical vapour deposition, Molecular beam epitaxy, Chemical synthesis. In 2004, two scientists produced the graphene by micromechanical cleavage. The traditional micromechanical method is using tape to peel the graphene slice from large crystal, or using expanded pyrolytic graphite to abrase each other to get the unshaped graphene. In industrial production, the graphene is manufactured by growth on slice and chemical synthesis. For growth method, the highly oriented pyrolytic graphite (HOPG) was penetrated into substrate (usually SiC slice), and treated in ultrahigh vacuum and under pressure, then the graphene would produce on the substrate. The most traditional method of chemical synthesis method is Hummers method, use potassium permanganate (KMnO₄), sodium nitrate (NaNO₃) and sulfuric acid can produce the oxidized graphene, then use hydrazine hydrate to reduce oxidized graphene to produce the graphene.

The graphene is a kind of special electronic materials, and usually used as semiconductor, so the products of graphene usually do not have shapes. However, there is still not a specific application of graphene, because of its special properties. The carbon atoms in graphene structure has 4 bonds: one σ bond with each three atoms nearby and one π bond oriented out of plane. This special structure gives graphene excellent conductibility and optical properties.

Figure 3: the micro structure of graphene