Shedding light on epitaxial graphene by using high-resolution x-ray photoelectron spectroscopy

February 2, 2023, 11:00h

J. Heyrovský Institute, Brdička Lecture Hall

Alessandro Baraldi Physics Department, University of Trieste, Trieste - Italy

Abstract:

Core level photoelectron spectroscopy is a widely used experimental technique to probe physical and chemical processes taking place at solid surfaces. As core levels are highly localized, changes in core electron binding energies can be used as a local probe of the variation in the electrostatic potential of atoms located in different local environments. In the case of epitaxial graphene this is valid for both, carbon atoms forming the 2D honeycomb lattice, and first-layer substrate atoms. Indeed the core-level energies of the substrate atoms reflect the changes in the electronic distribution because of interaction with the graphene layer. Since core level binding energy shifts can be calculated with a high level of accuracy using density functional theory, the close comparison between experimental and theoretical results represents a key ingredient to obtain precious information about the properties of epitaxial graphene. In this talk I will show how this approach can be used in order to study growth mechanisms using different molecular precursors on a wide range of transition metals, oxide films and bimetallic surface alloys, the interaction with the substrate, the thermal stability and the templating effect for the growth of nanoclusters.

Alessandro Baraldi is Professor of Experimental Condensed Matter Physics at the University of Trieste, where he serves also as Deputy Rector for Scientific Research and Doctorates. He is responsabile of the Nanoscale Materials Laboratory at Elettra – Sincrotrone Trieste where he carries on his scientific research since the 90’s.