X‐ray reflectivity from curved surfaces as illustrated by a graphene layer on molten copper. (1st April 2022)

• Record Type: Journal Article
• Authors: Konovalov, Oleg V.; Belova, Valentina; La Porta, Francesco; Saedi, Mehdi; Groot, Irene M. N.; Renaud, Gilles; Snigireva, Irina; Snigirev, Anatoly; Voevodina, Maria; Shen, Chen; Sartori, Andrea; Murphy, Bridget M.; Jankowski, Maciej
• Is Part Of: Journal of synchrotron radiation. Volume 29:Part 3(2022)
• Page Start: 711
• Page End: 720
• Publication Date: 2022-04-01
• Subjects: X‐ray reflectivity -- curved surfaces -- methods -- synchrotron; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577522002053
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : A method of X‐ray reflectivity data reconstruction from scattering measurements on spherically curved surfaces is proposed and tested on solid and liquid surfaces. Abstract : The X‐ray reflectivity technique can provide out‐of‐plane electron‐density profiles of surfaces, interfaces, and thin films, with atomic resolution accuracy. While current methodologies require high surface flatness, this becomes challenging for naturally curved surfaces, particularly for liquid metals, due to the very high surface tension. Here, the development of X‐ray reflectivity measurements with beam sizes of a few tens of micrometres on highly curved liquid surfaces using a synchrotron diffractometer equipped with a double crystal beam deflector is presented. The proposed and developed method, which uses a standard reflectivity gθ–2gθ scan, is successfully applied to study in situ the bare surface of molten copper and molten copper covered by a graphene layer grown in situ by chemical vapor deposition. It was found that the roughness of the bare liquid surface of copper at 1400 K is 1.25 ± 0.10 Å, while the graphene layer is separated from the liquid surface by a distance of 1.55 ± 0.08 Å and has a roughness of 1.26 ± 0.09 Å.