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

Epitaxial Sr0.98Mn0.02TiO3 (SMTO) thin films were grown on conductive-oxide electrodes (LaNiO3 – LNO, SrRuO3 – SRO, and La0.67Sr0.33MnO3 – 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 (Ur) 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 Ur 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. Energy-band diagrams of Sr0.98Mn0.02TiO3 films grown on LaNiO3, SrRuO3 and La0.67Sr0.33MnO3 electrodes. [Display omitted] •High energy-storage density of 113.3 J/cm3 achieved in SMTO/LSMO thin-film capacitor.•Large Schottky-barrier height improves the breakdown strength of film capacitors.•Good thermal stability (till 200 °C) and excellent fatigue-cycling reliability (till 1010 cycles).