Dependence of dielectric and photovoltaic properties of Pt/PLZT/LNO on the temperature and La doping content

In this study, Pb_1−xLa_x(Zr_0.52Ti_0.48)O₃/LaNiO₃ (PLZT/LNO) heterostructures with different doping contents of La (x = 0.02–0.15) were prepared on a Si substrate by sol–gel process. First, the effects of the La doping content on the crystal structure, electric hysteresis loop, and dielectric performance of the PLZT thin film were investigated. With the increase in the La doping content, the results revealed that the XRD diffraction peaks of the PLZT thin film shifted to large angles, indicative of the decrease in the film grain size; meanwhile, the residual polarization intensity and coercive field strength of the thin film decreased. The dielectric-temperature spectrum revealed that with the increase in the La doping content, the Curie temperature of the PLZT thin film gradually decreased, while the relative dielectric constant tended to first decrease and then increase. When x (La) was 0.08, the constant reached the minimum. Furthermore, the dependences of the photovoltaic characteristics of the PLZT thin films on the temperature and La doping content were investigated. Under the same test temperature, the open-circuit voltage of the PLZT film tended to first increase and then decreased with the increase in the La doping content. When x (La) = 0.08, the open-circuit voltage reached the maximum. For PLZT with the same doping content of La, the open-circuit voltage also increased first and then decreased with increasing temperature. When T = 223 K and x (La) = 0.08, the open-circuit voltage reached the maximum of around 693 mV.