BaZrO3/MgO-templated epitaxy showing a conductivity increase of three orders of magnitude for the Ba0.95La0.05SnO3 films on Al2O3 substrates, with very high transparency and X-band electromagnetic shielding

Abstract

Acknowledgements: This work was supported by national R&D programs of the National Research Foundation of Korea funded by the Ministry of Science and ICT (project nos. NRF-2021M3F3A2A03015439, NRF-2021R1C1C1005042, and NRF-2018R1A5A1025511). We also acknowledge partial support from national R&D programs of the National Research Foundation of Korea funded by the Ministry of Education (project no. NRF-2021R1A6A3A13043948) and the DGIST R&D program of the Ministry of Science and ICT of Korea (project nos. 22-HRHR+-05, 22-CoE-NT-02, and 22-SENS-1). S.L. and J.L.M.-D. would like to thank Trinity College at Cambridge for partial support. J.L.M.-D. would like to thank the EU-H2020-ERC-ADG # 882929 grant, EROS, and the Royal Academy of Engineering CIET1819_24 for partial support.AbstractTransparent conductors with electromagnetic shielding capabilities (TC-EMS) are rare, despite their significant potential for creating new functionalities in energy and military applications. Here, we investigate the potential of La-doped BaSnO3 (BLSO) for TC-EMS since its epitaxial film has been known to have low sheet resistance and high visible transmittance. However, films grown on industrially practical Al2O3 substrates exhibit a sheet resistance three orders of magnitude higher than that of reported films grown on perovskites. Here, this problem is addressed by templating a BaZrO3/MgO bilayer on (0001)-oriented Al2O3 substrates to yield single-crystalline BLSO epitaxial films. The absence of grain boundaries in the epitaxial films minimizes the electron scattering. Due to the affirmative correlation between the conductivity and crystallinity, 5% La doping is optimal among the 5−20% La concentrations studied; these 480-nm-thick films have the highest crystallinity and the lowest sheet resistances of ~28 Ω ▯−1; this value is similar to that of single-crystalline levels. Due to their very high transmittances (~82% in a range 400−1000 nm) and effective X-band electromagnetic shielding (~18.6 dB), the BLSO epitaxial films grown on Al2O3 have great potential to be used for inexpensive TC-EMS applications.</jats:p