Field of Expertise: Advanced Material Science
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Field of Expertise: Advanced Material Science | |
Preparation and Electron Microscopy of Graphene Graphene, a single atom layer of graphite, is the first representative of a completely new class of materials, which are considered to be a future key technology due to their unusual physical properties. It is very promising for a wide field of applications. For instance the usage for building sensors with single-molecule sensitivity, flexible transparent electrodes in displays and solar cells, fast semiconductors, investigations of quantum mechanical phenomena at room temperature or solely water permeable membranes, just to mention a few, are imaginable. For the characterization of mono- and few-layer graphene as well as for other two-dimensional crystals, (scanning) transmission electron microscopy (S/TEM) is among the most efficient techniques since it provides direct insight into the atomic structure of the material along with some of its properties and its thickness. Since Novoselov and Geim invented the famous "scotch tape method" for graphene synthesis in 2004 plenty of other preparation methods were presented. The key criterion for the success of the preparation procedure is the number of atomic layers in the resulting graphene flakes; the identification of these monoatomic areas is essential for the subsequent transfer step to the TEM grid. Therefore, optical microscopy, atomic force microscopy (AFM) and Raman spectroscopy are methods of choice for pre-TEM characterization. |