Energy storage performance of silicon-integrated Sr0.98Mn0.02TiO3 thin film capacitors

Epitaxial Sr_0.98Mn_0.02TiO₃ (SMTO) thin films were grown on conductive-oxide electrodes (LaNiO₃ – LNO, SrRuO₃ – SRO, and La_0.67Sr_0.33MnO₃ – LSMO) buffered SrTiO₃/Si substrates, using a pulsed laser deposition method. The effect of the bottom electrodes on the breakdown and energy storage density of SMTO thin films have been systematically investigated. A high recoverable energy storage density (U_r) of 113.3 J/cm³ was achieved at 7.30 MV/cm in an SMTO/LSMO film, which is significantly higher than that of SMTO/SRO (100.4 J/cm³ at 7.15 MV/cm), and SMTO/LNO (67.2 J/cm³ at 6.30 MV/cm) films. This high U_r value is simultaneously attributed to an improvement in both polarization and breakdown strength induced by a high Schottky barrier height at the SMTO/LSMO junction. In addition, the SMTO/LSMO film demonstrated excellent thermal stability (up to 200 °C), and good fatigue endurance (up to 10¹⁰ cycles), indicating its suitability for long-term operation and use in harsh environmental conditions of high energy storage capacitor applications.