Effects of deposition temperature on structure and properties of (K _0.48Na_0.52)NbO₃ ferroelectric thin films by pulsed laser deposition

Highly [001] oriented lead-free (K_0.48Na_0.52)NbO ₃ thin films have been prepared on Pt/TiO₂/SiO ₂/Si substrates by pulsed laser deposition. The microstructure and electrical properties of the thin films are a strong function of deposition temperature. Highly preferentially [001] oriented thin films were obtained at the deposition temperature of 740 °C. The film exhibits a dielectric constant of 422 and a dielectric loss of 0.058 at 1 kHz. The P-E hysteresis loop shows that the film possesses a large remnant polarization of 11 μC/cm ² and a moderate coercive field of 72 kV/cm. The Ohmic conduction is dominant at the low field for the films except the film deposited at 680 °C. However, the Poole-Frenkel conduction mechanism is dominant at the high field for the films except the film deposited at 700 °C.