Direct Epitaxial Growth of Polar Hf0.5Zr0.5O2 Films on Corundum

Autor: Eduardo Barriuso, Panagiotis Koutsogiannis, David Serrate, Javier Herrero-Martín, Ricardo Jiménez, César Magén, Miguel Algueró, Pedro A. Algarabel, José A. Pardo
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Nanomaterials, Vol 12, Iss 7, p 1232 (2022)
Druh dokumentu: article
ISSN: 2079-4991
DOI: 10.3390/nano12071232
Popis: Single-phase epitaxial Hf0.5Zr0.5O2 films with non-centrosymmetric orthorhombic structure have been grown directly on electrode-free corundum (α-Al2O3) substrates by pulsed laser deposition. A combination of high-resolution X-ray diffraction and X-ray absorption spectroscopy confirms the epitaxial growth of high-quality films belonging to the Pca21 space group, with [111] out-of-plane orientation. The surface of a 7-nm-thick sample exhibits an atomic step-terrace structure with a corrugation of the order of one atomic layer, as proved by atomic force microscopy. Scanning transmission electron microscopy reveals that it consists of grains with around 10 nm lateral size. The polar nature of this film has been corroborated by pyroelectric measurements. These results shed light on the mechanisms of the epitaxial stabilization of the ferroelectric phase of hafnia.
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