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Electron Microscopy of Advanced Materials

Contact: Prof. Ursel Bangert

Bernal Chair of Microscopy and Imaging,
Department of Physics and Energy,
University of Limerick

E-mail: Ursel.Bangert@ul.ie

Tel. +353-61-213499

 

Owing to improvements in magnetic lenses, which can now be very efficiently aberration corrected, transmission electron microscopy TEM) has advanced to the level of sub-Angstrom imaging and spectroscopy. As part of the Bernal project UL is acquiring a top-of-the range TEM, which will enable staff in the group to engage in developments and advancements of TEM based imaging and spectroscopy. TEM is an essential method for microstructural investigations of materials, especially with regards to failure mechanisms, not only regarding mechanical but, importantly, electronic device failure (e.g., in   semiconductors). Since the demonstration of the existence of two-dimensional (2-D) materials, the latter have raised excitement globally with exponentially increasing numbers of potential applications, heralding a new era of (advanced) materials. This excitement is due to their amazing and unrivalled properties concerning mechanical strength, electrical transport, and light-emission and -harvesting, at the same time enabling extreme miniaturisation for flexible nano- electronics. Prof. U. Bangert has worked on the 2-D material graphene since its discovery and, while at the University of Manchester, collaborated with Geim and Novoselov who were awarded the Nobel Prize for their pioneering work on this material in 2010. Graphene itself lacks electronic properties that would allow direct implementation in electronics, and other 2-D materials, e.g., transition metal dichalcogenides have recently entered the scene as promising candidates for use in nano-electronics.What is more, stacking different 2-D materials together, one can form novel hetero-structures for completely new functionalities.Putting these predictions into praxis relies on being able to reveal structure-related problems. For example there are severe difficulties with metal contacting of 2-D materials for making electronic devices; these could only be uncovered by using atomic-scale characterisation methods.

There exist also topographic curiosities, e.g., 2-D materials are not stable unless they assume 3-D equivalent forms, i.e., they ripple. The group has strong collaborations with Centres of excellence in microscopy (e.g., the Daresbury SuperSTEM, UK, and the Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Juelich, Germany) as well with the Graphene Group at Manchester. Collaborations concerning 2-D materials research are also established with Leeds and Liverpool Universities (UK), Manchester Metropolitan University (UK), Goettingen University (Germany) and Trinity College Dublin/CRANN.