Ultrasmooth Ru(0001) Films as Templates for Ceria Nanoarchitectures

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• 作者：Marc Sauerbrey ; Jan Höcker ; Meikel Wellbrock ; Marco Schowalter ; Jon-Olaf Krisponeit ; Knut Müller-Caspary ; Andreas Rosenauer ; Gang Wei ; Lucio Colombi Ciacchi ; Jens Falta ; Jan Ingo Flege
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4216-4224
• 全文大小：546K
• 年卷期：0
• ISSN：1528-7505

文摘

Single crystalline magnetron sputter-deposited Ru(0001) epitaxial thin films on c-plane sapphire were prepared and used as a template for reactive CeO₂ growth. Low-energy electron microscopy and diffraction, as well as transmission electron microscopy and atomic force microscopy, experiments were performed to investigate the crystallinity and morphology of the prepared films. Multiple cycles of Ar⁺ sputtering and high-temperature annealing produces films of exceptional surface quality. High-temperature reactive ceria growth leads to perfectly aligned triangular single-crystalline CeO₂(111) islands of extraordinary morphological and structural homogeneity. At the chosen growth conditions, ceria nucleation takes place only at V-shaped surface defects on the otherwise atomically flat Ru terraces, opening up the possibility to influence the nucleation by introducing artificial surface defects using standard etching techniques. Due to their high crystallinity and extraordinary surface quality, these substrates present a low-cost alternative to Ru single crystals for model studies in heterogeneous catalysis and also allow for the use of destructive investigation techniques and irreversible surface modifications.