Regensburg 2022 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session 2

MM 18.39: Poster

Dienstag, 6. September 2022, 17:30–20:00, P2

Quantification of intrinsic surface charges on MgO nanocubes using off-axis electron holography — •Yan Lu^1,2, Fengshan Zheng¹, Qianqian Lan¹, Michael Schnedler¹, Philipp Ebert¹, and Rafal E. Dunin-Borkowski¹ — ¹Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C 1) and Peter Grünberg Institute (PGI 5), Forschungszentrum Jülich, Jülich, Germanz — ²Beijing Key Lab and Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing, China

Metal oxide nanoparticles exhibit outstanding catalytic properties, believed to be related to the presence of oxygen vacancies at the particle surface. However, little quantitative is known about concentrations of point defects inside and on surfaces of these nanoparticles due to the challenges in achieving an atomically resolved experimental access. By employing off-axis electron holography, we demonstrate exemplarily using MgO nanoparticles as a methodology, which allows us to discriminate between mobile charges induced by electron beam irradiation and immobile charges associated with deep traps induced by point defects as well as distinguish between bulk and surface point defects. Counting the immobile charges provides a quantification of the concentration of F²⁺ centers induced by oxygen vacancies at the MgO nanocube surfaces.