Epitaxial RuO$_2$ and IrO$_2$ films by pulsed laser deposition on TiO$_2$(110)

Fuente: arXiv
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Main Authors: Keßler, Philipp, Waldsauer, Tim, Jovic, Vedran, Kamp, Martin, Schmitt, Matthias, Sing, Michael, Claessen, Ralph, Moser, Simon
Format: Preprint
Published: 2024
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author Keßler, Philipp
Waldsauer, Tim
Jovic, Vedran
Kamp, Martin
Schmitt, Matthias
Sing, Michael
Claessen, Ralph
Moser, Simon
author_facet Keßler, Philipp
Waldsauer, Tim
Jovic, Vedran
Kamp, Martin
Schmitt, Matthias
Sing, Michael
Claessen, Ralph
Moser, Simon
contents We present a systematic growth study of epitaxial RuO$_2$(110) and IrO$_2$(110) on TiO$_2$(110) substrates by pulsed laser deposition. We describe the main challenges encountered in the growth process, such as a deteriorating material flux due to laser induced target metallization or the delicate balance of under- vs over-oxidation of the 'stubborn' Ru and Ir metals. We identify growth temperatures and oxygen partial pressures of 700 K, $1\times 10^{-3}$ mbar for RuO$_2$ and 770 K, $5\times 10^{-4}$ mbar for IrO$_2$ to optimally balance between metal oxidation and particle mobility during nucleation. In contrast to IrO$_2$, RuO$_2$ exhibits layer-by-layer growth up to 5 unit cells if grown at high deposition rates. At low deposition rates, the large lattice mismatch between film and substrate fosters initial 3D island growth and cluster formation. In analogy to reports for RuO$_2$ based on physical vapor deposition, we find these islands to eventually merge and growth to continue in a step flow mode, resulting in highly crystalline, flat, stoichiometric films of RuO$_2$(110) (up to 30 nm thickness) and IrO$_2$(110) (up to 13 nm thickness) with well defined line defects.
format Preprint
id arxiv_https___arxiv_org_abs_2405_12878
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Epitaxial RuO$_2$ and IrO$_2$ films by pulsed laser deposition on TiO$_2$(110)
Keßler, Philipp
Waldsauer, Tim
Jovic, Vedran
Kamp, Martin
Schmitt, Matthias
Sing, Michael
Claessen, Ralph
Moser, Simon
Materials Science
We present a systematic growth study of epitaxial RuO$_2$(110) and IrO$_2$(110) on TiO$_2$(110) substrates by pulsed laser deposition. We describe the main challenges encountered in the growth process, such as a deteriorating material flux due to laser induced target metallization or the delicate balance of under- vs over-oxidation of the 'stubborn' Ru and Ir metals. We identify growth temperatures and oxygen partial pressures of 700 K, $1\times 10^{-3}$ mbar for RuO$_2$ and 770 K, $5\times 10^{-4}$ mbar for IrO$_2$ to optimally balance between metal oxidation and particle mobility during nucleation. In contrast to IrO$_2$, RuO$_2$ exhibits layer-by-layer growth up to 5 unit cells if grown at high deposition rates. At low deposition rates, the large lattice mismatch between film and substrate fosters initial 3D island growth and cluster formation. In analogy to reports for RuO$_2$ based on physical vapor deposition, we find these islands to eventually merge and growth to continue in a step flow mode, resulting in highly crystalline, flat, stoichiometric films of RuO$_2$(110) (up to 30 nm thickness) and IrO$_2$(110) (up to 13 nm thickness) with well defined line defects.
title Epitaxial RuO$_2$ and IrO$_2$ films by pulsed laser deposition on TiO$_2$(110)
topic Materials Science
url https://arxiv.org/abs/2405.12878