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O: Fachverband Oberflächenphysik

O 49: Poster Nanostructures at Surfaces

O 49.10: Poster

Dienstag, 18. März 2025, 18:00–20:00, P2

Surface Reconstructions and Photocatalysis of Thermally Reduced LiNbO₃ and BaTiO₃ Single Crystals — •Marta Macyk¹, Andrzej Jasicki¹, Llorenç Albons², Konrad Szajna¹, Martin Setvin², Dominik Wrana¹, and Franciszek Krok¹ — ¹Marian Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland — ²Department of Surface and Plasma Science, Charles University, Prague, Czech Republic

Perovskite oxides, such as BaTiO₃ (BTO) and LiNbO₃ (LNO), exhibit a wide range of different stoichiometries and crystal structures that make them ideal candidates for applications in optoelectronics and catalysis. Their properties can be tuned by the change of stoichiometry and the introduction of oxygen vacancies achieved by annealing under Ultra High Vacuum (UHV).

This poster presents a comparative study of surface reconstructions for tetragonal BaTiO₃(001) and hexagonal LiNbO₃(0001) after UHV annealing under low oxygen partial pressure. LEED analysis reveals a (1× 1) to (√5×√5)R26.6^∘ transition for BTO, while LNO undergoes a (1× 1) to (√3× 6)R30^∘ transition, ending with (3× 3) structure at temperatures near 1200^∘C. Morphological studies using SEM, STM, and AFM show the formation of nanowire structures aligned with the substrates’ crystallographic directions, offering insights into controlled surface engineering. Furthermore, photocurrent measurements at variable temperature were performed on the thermally modified crystals to evaluate their photocatalytic and pyrocatalytic activity under ambient conditions.

Keywords: perovskite oxides; thermal reduction; annealing; photocatalysis; nanowires