September 4, 2012 14:00 - 15:00
Empa, Dübendorf, Theodor-Erismann-Auditorium, VE102
The energetics of nanomaterials are typically dominated by (excess) surface and/or interface energy contributions. Hence the thermodynamics of reactions and phase transformations in nanostructured materials and thin-film systems generally deviate from the 'expected' behaviors for the bulk materials. Moreover the short diffusion distances in combination with the high density of surfaces and interfaces enable much faster kinetics for thermodynamic equilibration, which makes artificial, nano-sized systems very prone to degradation.
This talk will address recent advances in the thermodynamic description of reactions and phase transformations in nanomaterials. The principles and guidelines to construct generally applicable thermodynamic model descriptions of interface-controlled reactions and microstructural evolutions will be outlined. As an example, model predictions on the critical thickness for the amorphous-to-crystalline transition of ultrathin (< 10 nm) oxide films on their metals are compared with experiments. Furthermore, predictions and experimental verifications of the Al-catalyzed crystallization of amorphous Si thin films are presented, which allow the low-temperature (< 200 ºC) manufacturing of high-efficiency solar cells and crystalline-Si-based nanostructures on cheap and flexible substrates such as glasses, plastics and possibly even papers.
Dr. Lars Jeurgens was born in the Netherlands, where he studied Geology at Utrecht University. After his graduation in 1996, he worked shortly as a researcher at the Shell Exploration and Production Laboratory in Rijswijk. Lars then obtained his PhD in materials sciences at Delft University of Technology in 2001. After a postdoctoral period working for the Dutch technology foundation (STW), he moved to the Max Planck Institute for Metals Research in Stuttgart (Germany) in 2003, to lead a research group on Reactions and Phase Transformations at Surfaces and Interfaces within the department of Prof. Mittemeijer. His research during this period was honoured with the Masing Gedächtnispreis of the Deutsche Gesellschaft für Materialkunde (DGM) in 2008. Lars joined the Empa, as the head of the new laboratory for Joining Technologies and Corrosion, since February 2012.
The language of the presentation is English.
Free entrance, guests are welcome
Dr. Anne Satir
Tel: 058 765 4562