Layer control of Sr1.8Bi0.2Nan-3NbnO3n+1 (n = 3–5) perovskite nanosheets: dielectric to ferroelectric transition of film deposited by Langmuir Blodgett method

So Yeon Yoo, Haena Yim, Ahrom Ryu, Chansoo Yoon, Bae Ho Park, Sahn Nahm, Ji Won Choi

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Abstract

Solution-based processable high-k 2-dimensional (2D) ferroelectrics have attracted significant interest for use in next-generation nanoelectronics. Although few studies on potential 2D ferroelectric nanosheets in local areas have been conducted, reports on the thin-film characteristics applicable to the device are insufficient. In this study, we successfully synthesize high-k 2D Sr1.8Bi0.2Nan-3NbnO3n+1 (octahedral units, n = 3–5) nanosheets by the engineering of the n of NbO6 octahedral layers with A-site modification, and realized ferroelectric characteristics in ultrathin films (below 10 nm). The nanosheets are synthesized by a solution-based cation exchange process and deposited using the Langmuir-Blodgett (LB) method. As increasing the NbO6 octahedral layer, the thickness of the nanosheets increased and the band gaps are tuned to 3.80 eV (n = 3), 3.76 eV (n = 4), and 3.70 eV (n = 5). In addition, the dielectric permittivity of the 5-layer stacked nanofilm increase to 26 (n = 3), 33 (n = 4), and 62 (n = 5). In particular, the increased perovskite layer exhibits large distortions due to the size mismatch of Sr/Bi/Na ions at the A-site and promotes local ferroelectric instability due to its spontaneous polarization along the c-axis caused by an odd n number. We investigate the stable ferroelectricity in Pt/ 5-layer Sr1.8Bi0.2Na2Nb5O16 / Nb:STO capacitor by polarization-electric field (P-E) hysteresis; the coercive electric field (Ec) was 338 kV cm−1 and the remnant polarization (Pr) 2.36 μC cm−2. The ferroelectric properties of ultrathin 2D materials could drive interesting innovations in next-generation electronics.

Original languageEnglish
Article number53
Journalnpj 2D Materials and Applications
Volume7
Issue number1
DOIs
Publication statusPublished - 2023 Dec

Bibliographical note

Funding Information:
This research was supported by the Korea Institute of Science and Technology Future Resource Program (2E32491), the National Research Foundation of Korea (NRF) grant funded by the Korean government (No. 2021R1A2C2010695), Green New Deal 100 Promising Company 100 R&D Program (2MRC190) funded by the Ministry of SMEs and Stratups (MSS, Korea), Korea Basic Science Institute (National research Facilities and Equipment Center) grant funded by the Ministry of Education (Grant No. 2022R1A6C101A754) and National R&D Programs (No. 2022R1A2C3004135) through the National Research Foundation of Korea (NRF) funded by Ministry of Science.

Publisher Copyright:
© 2023, Springer Nature Limited.

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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