(111)-oriented epitaxial (K0.5Na0.5)NbO3 films of 2 μm thickness were deposited at 240 °C on (111)cSrRuO3//(111)SrTiO3 substrates by a hydrothermal method. Scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDS) mapping revealed that a K-rich interfacial region existed in the obtained films. Although the as-deposited films were annealed between 240 and 600 °C in O2 atmosphere, the crystal structure did not markedly change. On the other hand, the leakage current density drastically decreased from 10%2-100 to 10%6 A/cm2 at +80 kV/cm after annealing above 240 °C. In addition, the relative dielectric constant (er), remanent polarization (Pr), and piezoelectric constant (d33,PFM) increased with increasing annealing temperature from 300 to 600 °C, and their values were respectively 840, 5.7 μC/cm2, and 64 pm/V for the films annealed at 600 °C.
ASJC Scopus subject areas
- Physics and Astronomy(all)