Springe direkt zu Inhalt

<h1><font size="4" color="#6600CC">Graphene</font></h1>

Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D graphite. Theoretically, graphene has been studied for sixty years and widely used for describing properties of various carbon-based materials. Graphene was presumed not to exist, because it was thought to be unstable with respect to the formation of curved structures such as fullerenes and nanotubes. Only in 2004, unexpectedly, graphene has been experimentally isolated and characterised [1,2].

The electronic structure of graphene is unique: the conical valence and conduction bands meet at a single point (Dirac point) in the momentum space; around this point the energy varies linearly with the magnitude of the momentum. This implies that the charge carriers move through the solid with zero mass and constant velocity, i.e. its electrons move ballistically over submicron distances, even under ambient conditions [2]. The electronic structure rapidly evolves with the number of layers, approaching the 3D limit of graphite already at 10 layers.  Due to its unusual electronic properties, reduced dimensionality and good stability, graphene has enormous potential for use in ultra-fast electronic transistors. Furthermore, bulk electrodes, quantum dots and barriers can be made out of graphene, allowing for a single-electron transistor made entirely of the same material. Graphene can be used for many applications: in composite materials and in electric batteries due to its large surface-to-volume ratio and high conductivity, in field emitters and for transparent membranes due to its atomic thickness, in micromechanical resonators due to its robustness and light weight, and chemical detectors due to it selective reactivity.

  1. K. S. Novoselov, D. Jiang, F. Schedin, T. J. Booth, V. V.Khotkevich, S. V. Morozov (2005): Two-dimensional atomic crystals. Proc. Natl. Acad. Sci. USA 102, 10451

  2. A. K. Geim, K. S. Novoselov (2007): The raise of graphene, Nature Materials, 6, 183