講演情報
[20a-A309-9][Young Scientist Presentation Award Speech] Flexible BaTiO3 Epitaxial Films with Bulk-like Ferroelectricity and Piezoelectricity
〇Lizhikun Gong1, Binjie Chen1, Rui Yu1, Hiromichi Ohta2, Katayama Tsukasa2,3 (1.IST, Hokkaido Univ., 2.RIES, Hokkaido Univ., 3.JST-PRESTO)
キーワード：
Flexible oxide film、Conducting film
Flexible electronic devices based on epitaxially-grown oxide films have attracted considerable attention in recent years, owing to their diverse functions such as ferroelectricity and piezoelectricity. However, due to the limit of processing techniques, most of the perovskite oxides are only processible with poor crystal quality even though they were heteroepitaxially grown on a flexible single crystalline substrate like Mica, leading to much lower performances of film compared to epitaxial films on single crystalline oxide substrates. Recently, a Sr3Al2O6 (SAO) sacrificial layer was utilized to peel-off the epitaxial oxide films [1]. However, many cracks are introduced to the peel-offed film due to release of lattice strain in the case of BaTiO3 (BTO) on SAO buffered SrTiO3 substrate. To overcome this difficulty, we found covering a 300-nm-thick amorphous AlOx film on the epitaxial oxide film surface is effective to suppress crack generation [2]. In this study, we demonstrated a method to obtain flexible epitaxially-grown oxide films with ferroelectricity and piezoelectricity on arbitrary substrate. Through this method, large-size (25 mm2) crack-free epitaxially-grown rolled and flat BaTiO3 (BTO) sheets were obtained on glass or PET substrate with covered an amorphous AlOx/ITO bilayer film, by directly placing as-grown film in deionized water and transferring using tweezers (Fig. a), demonstrating the excellent flexibility and strong toughness of the film. The BTO films exhibited ferroelectricity and piezoelectricity similar to the bulk single-crystal (Fig. b and c). [1] Lu, D et al., Nat. Mater., 15, 1255-1260 (2016). [2] L. Gong et al., ACS Nano, 16, 21013-21019 (2022)