Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China , Hefei 230026, China.
Department of Physics and Astronomy, University of Nebraska , Lincoln, Nebraska 68588, United States.
ACS Appl Mater Interfaces. 2017 Jun 21;9(24):20484-20490. doi: 10.1021/acsami.7b02225. Epub 2017 Jun 7.
Solid-state dielectric film capacitors with high-energy-storage density will further promote advanced electronic devices and electrical power systems toward miniaturization, lightweight, and integration. In this study, the influence of interface and thickness on energy storage properties of SrTiO (STO) films grown on LaSrMnO (LSMO) electrode are systematically studied. The cross-sectional high resolution transmission electron microscopy reveals an ion interdiffusion layer and oxygen vacancies at the STO/LSMO interface. The capacitors show good frequency stability and increased dielectric constant with increasing STO thickness (410-710 nm). The breakdown strength (E) increases with decreasing STO thickness and reaches 6.8 MV/cm. Interestingly, the E under positive field is enhanced significantly and an ultrahigh energy density up to 307 J/cm with a high efficiency of 89% is realized. The enhanced E may be related to the modulation of local electric field and redistribution of oxygen vacancies at the STO/LSMO interface. Our results should be helpful for potential strategies to design devices with ultrahigh energy density.
具有高储能密度的固态电介质薄膜电容器将进一步推动先进的电子设备和电力系统朝着小型化、轻量化和集成化方向发展。在这项研究中，系统研究了 SrTiO（STO）薄膜在 LaSrMnO（LSMO）电极上生长时界面和厚度对储能性能的影响。横截面高分辨率透射电子显微镜揭示了 STO/LSMO 界面处的离子互扩散层和氧空位。电容器具有良好的频率稳定性和随 STO 厚度（410-710nm）增加而增加的介电常数。击穿强度（E）随 STO 厚度的减小而增加，达到 6.8MV/cm。有趣的是，在正电场下，E 显著增强，实现了高达 307J/cm 的超高能量密度，效率高达 89%。增强的 E 可能与 STO/LSMO 界面处局部电场的调制和氧空位的重新分布有关。我们的研究结果应该有助于设计具有超高能量密度的器件的潜在策略。
