Influence of annealing temperature on the microstructure, leakage current and dielectric properties of Na 0.5 Bi 0.5 (Ti,Zn)O 3 thin films

Lead-free Na 0.5 Bi 0.5 (Ti,Zn)O 3 (NBTZn) thin films were deposited on indium tin oxide (ITO)/glass substrates via a metal organic decomposition process and annealed at various temperatures from 450 to 600 °C. The influence of annealing temperature on crystallization and electrical properties were investigated. XRD measurement reveals that the film can be crystallized into single perovskite at an annealing temperature as low as 500 °C. The average grain size of the NBTZn sample increases with increasing the annealing temperature from 500 to 600 °C. The leakage current density also increases with the increase in annealing temperature probably due to the variation content of grain boundaries and oxygen vacancies. Compared with other samples annealed at 500 and 600 °C, the film prepared at 550 °C shows enhanced dielectric properties with a relatively high dielectric tunability of 36.4 % and low dissipation factor of 0.13 at 200 kHz.