Improvement of energy storage performance by controlling the crystallinity of Aurivillius BaBi4Ti4O15 thin films

We investigated the crystallinity, ferroelectric properties, and energy storage efficiency of Aurivillius BaBi 4 Ti 4 O 15 (BBTO) thin films epitaxially deposited on single-crystal (001) Rh substrates by pulsed laser deposition method. From X-ray diffraction experiments, it was confirmed that the BBTO thin films had a mixed crystallinity of a -oriented crystallinity and c -oriented crystallinity. The BBTO thin films fabricated by a low substrate temperature and a high deposition rate showed highly a- oriented crystallinity. On the other hand, the BBTO thin films deposited by a high substrate temperature and a low deposition rate showed improved crystallinity with highly c- oriented crystallinity. The BBTO thin film with the highly a -oriented crystallinity showed large remanent polarization, and the BBTO thin film with the highly c -oriented crystallinity showed small remanent polarization but excellent leakage current characteristics. In addition, the BBTO thin film with the highly c -oriented crystallinity exhibited superior energy storage characteristics with a high energy storage density of 32.5 J/cm 3 and a high efficiency of 0.8 compared to the BBTO thin film with the highly a -oriented crystallinity.