Graphene
The theory of graphene was first explored by Wallace in 1947 as a starting point for understanding the electronic properties of 3D graphite. The emergent massless Dirac equation was first pointed out by Semenoff, DiVincenzo and Mele. The earliest TEM images of few-layer graphite were published by Ruess and Vogt in 1948. An early, detailed study on few-layer graphite dates to 1962 when Boehm and colleagues reported producing monolayer flakes of reduced graphene oxide. Efforts to make thin films of graphite by mechanical exfoliation started in 1990, but nothing thinner than 50 to 100 layers was produced before 2004. Initial attempts to make atomically thin graphitic films employed exfoliation techniques similar to the drawing method. Multilayer samples down to 10 nm in thickness were obtained.
Walter de Heer
His nanotube work led to consideration of the properties of "opened" carbon nanotubes and the development of graphene-based electronics, starting in 2001. Anticipating that patterned graphene structures would behave like interconnected carbon nanotubes, he proposed several avenues of graphene preparation, including exfoliation of graphite flakes to oxidized silicon wafers and epitaxial growth on silicon carbide. The latter was deemed most promising for large-scale integrated electronics, and was funded by Intel Corporation in 2003. In 2004, the group was awarded additional funding from the National Science Foundation for the pursuit of graphene science. The first paper, "Two dimensional electron gas properties of ultrathin epitaxial graphite", was presented in March 2004 at a meeting of the American Physical Society and published in December under the title, "Ultrathin epitaxial graphite: Two dimensional electron gas properties and a route towards graphene based electronics". This paper, based primarily on data documented in 2003, describes the first electrical measurements of epitaxial graphene, reports fabrication of the first graphene transistor, and outlines the desirable properties of graphene for use in graphene-based electronics. De Heer and coworkers Claire Berger and Phillip First hold the first patent on graphene-based electronics, provisionally filed in June 2003. The approach championed by de Heer has the advantage of producing graphene directly on a high-quality electronic material (silicon carbide) and does not require isolation or transfer to any other substrate.