Water-soluble CaO sacrificial layer heteroepitaxially grown on yttria-stabilized zirconia substrate for large ferroelectric BaTiO3 sheets†
c
and
Tsukasa
Katayama
*cd
Abstract
Ferroelectric perovskite oxide sheets with a high orientation and crystallinity are suitable for various applications. A promising method for their synthesis involves the combination of epitaxial growth with sacrificial layers that can be dissolved in solvents. However, the practical applications of these sacrificial layers are limited. They are typically grown on substrates such as SrTiO3 single crystals, which have not yet been scaled up for large-area applications. In addition, during the lift-off process, a high density of cracks are often formed in the ferroelectric sheets. To address these issues, we used a CaO sacrificial layer in this study. We deposited a ferroelectric BaTiO3 epitaxial layer on the CaO sacrificial layer, which was epitaxially grown on a [110]-oriented yttria-stabilized zirconia (YSZ) substrate, together with a protective Al2O3 glass layer. After dissolving the CaO layer in pure water, we successfully obtained a crack-free freestanding BaTiO3 sheet with a lateral size of 5 mm × 2 mm. The resulting BaTiO3 sheet exhibited room-temperature ferroelectricity and piezoelectric properties with a large d33 value of 270 pm V−1 owing to the release of strain from the substrate. In addition, the YSZ substrate could be reused. Our study expands the range of water-soluble sacrificial layers and substrates for obtaining large ferroelectric and piezoelectric oxide epitaxial sheets.
Please wait while we load your content...
