Effects of heat treatment on the electrical and electromechanical properties of hydrothermally synthesized epitaxial (K0.51Na 0.49)NbO3 films were investigated. The film composition and crystal structure did not markedly change with heat treatment from 240 to 600°C in O2 atmosphere. However, the leakage current density drastically decreased from the order of 101 to 10%5A/ cm2 at 50kV/cm after heat treatment at 240 °C. The relative dielectric constant, remanent polarization, and transverse piezoelectric constant increased with increasing heat treatment temperature from 300 to 600°C (from 330 to 750 in εr, from 5.4 to 14 μC/cm 2 in remanent polarization, and from 41 to 56pm/V in transverse piezoelectric response). H2O desorption of 12ppm was detected in epitaxial (K0.51Na0.49)NbO3 films by thermal desorption spectroscopy measurement. Such H2O desorption can be related to the improvement of the electrical and electromechanical properties of the hydrothermally synthesized epitaxial (K0.51Na 0.49)NbO3 films.
ASJC Scopus subject areas
- Physics and Astronomy(all)