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 Karl Franzens University Graz

Graz University of Technology 

The physics of nano-carbons explored by high-resolution electron microscopy
Jannik C. Meyer
Physik Nanostrukturierter Materialien, Universität Wien
17:15 - 18:15 Tuesday 13 November 2012 TUG P2

Graphene is a crystalline single layer of carbon atoms that can be described as an individual atomic plane extracted from graphite. It is an outstanding new material that promises a wide range of new applications and scientific insights. It is also closely related to carbon nanotubes, fullerenes or graphite, which can be described as rolled-up or stacked graphene sheets. Hence, the graphene structure and its defects are of outstanding interest for the science and applications of these new materials.
The study of nano-carbons and other low-atomic number materials remains a particular challenge for high resolution transmission electron microscopy (HRTEM)owing to their intrinsically low contrast and high susceptibility to radiation damage.
However, the recent developments in aberration-corrected electron optics open a route to an atomically-resolved study of these materials at reduced electron energies, below the knock-on threshold of carbon atoms in graphene. I will present recent insights to this class of materials from electron microscopic studies with single-lightatom precision. Static deformations, topological defects, various vacancy configurations, the two-dimensional equivalent of dislocations, grain boundaries and substitutional dopants can be analyzed and exact atomic configurations are obtained.
I will show that also insights to the charge distribution in point defects are possible from an HRTEM analysis. Moreover, I will discuss important aspects of radiation damage in the context of radiation sensitive nano-carbon materials.