Effects of Zn2+ doping content on the structure and dielectric tunability of non-stoichiometric [(Na0.7K0.2Li0.1)0.45Bi0.55]TiO3+δ thin film

Abstract

The Zn2+ doped non-stoichiometric [(Na0.7K0.2Li0.1)0.45Bi0.55](Ti1−xZnx)O3+δ (NKLBTZnx, x = 0–4 at.%) thin films were deposited on fluorine-doped tin oxide/glass substrates via a metal organic decomposition method. The effect of Zn2+ doping content on microstructure, insulating characteristic and dielectric properties were mainly investigated. All the thin films exhibit similar single perovskite structures without detectable secondary phase and the grain size gradually decreases with the increase of Zn2+ doping content. Compared with other films, NKLBTZn0.01 thin film shows enhanced insulating characteristic with lower leakage current, and improved dielectric properties with a relatively higher dielectric tunability and lower dielectric loss. Moreover, with the increasing of electric field or decreasing of measuring frequency, the dielectric tunability is progressively increased. The tunability and figure of merit for the NKLBTZn0.01 thin film at 300 kV/cm and 1 kHz are 40.1 % and 7.0, respectively. These findings suggest that NKLBTZn thin film has potential applications in microwave dielectric devices.