The Electron Spectroscopy Division of the French Vacuum Society cordially invites you to participate to the 6th edition of its scientific webinars, to be held Tuesday, December 12th, 2023 at 10 am, on the topics below :

Part 1: "Young scientist talk" (20 min, including questions)
"Surface potential at the ferroelastic domain and domain walls in CaTiO3"
Presented by:
Grégoire Magagnin (INL, EC-Lyon, France)

Part 2: "Main talk" (45 mn)
"Low energy electron microscopy: from basic principles to surface dynamics
Presented by:
Frédéric LEROY (CiNaM, Aix-Marseille Université, France)


In this talk, I will first discuss the principle of low energy electron microscopy (LEEM). I will describe the main imaging modes of material by LEEM using the reflected and diffracted electrons by the surface and then give an overview of the most important related techniques (LEED, spin-polarized LEEM, PEEM). Then I will discuss one the major advantages of LEEM: the possibility to study in real-time the spatio-temporal dynamics of surfaces under non-equilibrium conditions through selected examples in the context of semiconductor physics. The thermal de-oxidation and the solid state dewetting of silicon thin films on silica (Silicon-On-Insulator) will be described, taking advantage of the multiscale potentialities of LEEM. Then I will focus on the growth of metallic eutectic nanodroplets on silicon surfaces, as seeds for nanowire growth. At last I will show that LEEM allows addressing electro- and thermo-migration processes at surfaces with unprecedented accuracy by measuring the drift velocity of single atomic step edges.

Short CV:

Frédéric Leroy received the M.Eng. degree from the Institut National Polytechnique de Grenoble, France, in 1999, and the Ph.D. degree in physics from Université Joseph Fourier, Grenoble, France, in 2004 in the field of self-organized growth of nanostructures by molecular beam epitaxy. He was a Post-Doctoral Fellow at the Max Planck for Solid state Physics, Stuttgart, Germany. He was then an Associate Professor at Aix-Marseille University, Marseille, France, and since 2016 Professor of Physics. His research is done at the Interdisciplinary Center for Nanoscience of Marseille. His research focuses on the dynamics of surfaces and thin films under non-equilibrium conditions. He aims at identifying the mechanisms of atomic transport related to thin film growth, solid state reactions or surface phase transitions. His research interests include solid state dewetting of thin films, electro- and thermo-migration processes and ferroelectric-ferroelastic properties of epitaxial thin films.