Microstructure and nanoscopic porosity in black Pd films

0539094 - FZÚ 2021 RIV PL eng J - Journal Article
Melikhova, O. - Čízek, J. - Hruška, Petr - Lukáč, František - Novotný, Michal - More Chevalier, Joris - Fitl, P. - Liedke, M.O. - Butterling, M. - Wagner, A.
Microstructure and nanoscopic porosity in black Pd films.
Acta Physica Polonica A. Roč. 137, č. 2 (2020), s. 222-226. ISSN 0587-4246. E-ISSN 1898-794X
R&D Projects: GA ČR GA18-09347S
Institutional support: RVO:68378271 ; RVO:61389021
Keywords : positron-annihilation * lifetimes * palladium * thin film
OECD category: Coating and films; Fluids and plasma physics (including surface physics) (UFP-V)
Impact factor: 0.577, year: 2020
Method of publishing: Open access
https://doi.org/10.12693/APhysPolA.137.222

In the present work the microstructure of a black Pd film prepared by thermal evaporation and a glossy Pd film deposited by magnetron sputtering was compared. While the glossy Pd film exhibits typical polycrystalline structure with column-like grains, the black Pd film has fractal-like porous structure. Positron annihilation spectroscopy revealed that positronium is formed in nanoscopic cavities of the black Pd film. In conventional metals positronium does not form due to screening by conduction electrons. However, in porous metals containing nanoscopic porosity a thermalized positron may pick an electron on inner surface of a pore and escape into a cavity forming positronium.
Permanent Link: http://hdl.handle.net/11104/0316842