Tailoring the position of the inserted Al2O3 insulating layer in the relaxor PLZT films for high-performance energy-storage applications

Thin-amorphous Al2O3 (AO) insulating layers inserted into the SrRuO3-top-electrode/Pb0.9La0.1Zr0.52Ti0.48O3 (PL)/SrRuO3-bottom-electrode/Si structures have been developed for enhancing the energy-storage performance of dielectric thin-film capacitors. It is found that the relaxor-paraelectric transition is observed by the insertion of the AO layer, and the paraelectric behavior of the films becomes stronger with the movement of the AO layer into the PL layer. Herein, a marked enhancement in breakdown strength from 2.5 to 5.8 MV/cm has been achieved in the PL single-film and PL/AO multilayer-film, which is the result of the simultaneous contributions of amorphous AO and pyrochlore-phase PL layers. As a result, an ultrahigh-recoverable energy-storage density of 90.7 J/cm3 and excellent energy-efficiency of 75.2% are simultaneously achieved in the PL/AO multilayer-film via the structure modulation. The findings provide an effective way to enhance the energy-storage density and breakdown strength of dielectric films via a combination of relaxor PL and amorphous AO layers.