Highly heterogeneous epitaxy of flexoelectric BaTiO<sub>3-δ</sub> membrane on Ge.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35637222.
- Also identified by DOI 10.1038/s41467-022-30724-7 and PMC identifier 9151678.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The integration of complex oxides with a wide spectrum of functionalities on Si, Ge and flexible substrates is highly demanded for functional devices in information technology. We demonstrate the remote epitaxy of BaTiO<sub>3</sub> (BTO) on Ge using a graphene intermediate layer, which forms a prototype of highly heterogeneous epitaxial systems. The Ge surface orientation dictates the outcome of remote epitaxy. Single crystalline epitaxial BTO<sub>3-δ</sub> films were grown on graphene/Ge (011), whereas graphene/Ge (001) led to textured films. The graphene plays an important role in surface passivation. The remote epitaxial deposition of BTO<sub>3-δ</sub> follows the Volmer-Weber growth mode, with the strain being partially relaxed at the very beginning of the growth. Such BTO<sub>3-δ</sub> films can be easily exfoliated and transferred to arbitrary substrates like Si and flexible polyimide. The transferred BTO<sub>3-δ</sub> films possess enhanced flexoelectric properties with a gauge factor of as high as 1127. These results not only expand the understanding of heteroepitaxy, but also open a pathway for the applications of devices based on complex oxides.