Achieving Ultrahigh Breakdown Strength and Energy Storage Performance through Periodic Interface Modification in SrTiO3 Thin Film

A periodic layer structure consisting of sol–gel-derived SrTiO3 and anodized Al2O3 has been designed and fabricated by interface engineering. Utilizing the anodized Al2O3 to be the blocking layer, not only the local high electric field around the hole and crack defects could be significantly reduced but also, and equally important, the blocking layer undertaking higher electric field could effectively decrease the breakdown probability of a SrTiO3 layer based on the finite element analysis. As the sample has been modified, the barrier height of the charge carrier was increased through fitting the conductance activation energy (Hc). In addition, the space charge-limited conductance mechanism was almost eliminated according to the fitted results in the ln E–ln J diagram, indicating that most of the charge carrier released from traps were blocked or isolated by the Al2O3 layer. As a result of the periodic interface modification, the leakage current was decreased 2 orders of magnitude and the breakdown strength was enhanced from 144.13 to 754.23 MV m–1. More importantly, the ultimate energy density is up to 39.49 J cm–3, which is 1505% greater than the sample without interface modification