Dr Thomas Walther
Tel: +44 (0)114 22 25891
Research Group: Semiconductor Materials & Devices
I received my undergraduate degree in physics from RWTH Aachen in 1993 and my PhD in materials science from the University of Cambridge in 1996/97. I was a postdoc at CEA Grenoble, Université d’Aix-Marseille (both in France) and University of Bonn (in Germany) where I later became assistant professor in the chemistry department. After a short spell at a new research centre where I sat up an electron microscopy lab in the same city, I joined the University of Sheffield as Senior Lecturer in 2006 and was promoted to a readership in 2010.
My research focuses on electron microscopy as a fundamental tool to measure chemical changes at the interfaces between different materials with atomic resolution. This can produce fantastic images that directly show where the atoms are located!
My research is relevant for understanding epitaxial growth processes as well as degradation and failure of semiconductor devices, such as transistors, light-emitting diodes, lasers and solar cells: atoms can sometimes move to lattice positions where they should not be, their agglomeration producing extended lattice defects called dislocations that can multiply and finally lead to device failure. These studies bridge the gap from fundamental science to applied engineering.
My research involves aspects of electron optics, solid state physics and inorganic chemistry as it combines different experimental methods of high-resolution analytical electron microscopy, based on inelastic electron scattering and X-ray photon generation, with detailed modelling of atomic movements in solids. Presently, this methodology is expanded into materials for energy conversion and storage, such as electrodes in batteries.