| Abstract Scope |
In this talk, we show our in-situ TEM results on the newly observed micromechanisms of dielectric breakdown in oxide nanocrystals using the advanced Hysitron PI95 TEM specimen holder and newly developed specimen preparation approach. First, we discuss the different breakdown mechanisms in TiO2 (i.e., rutile-to-anatase transition, amorphization/melting, and ablation) which depend on the field strength of applied voltages. Then, we discuss the electron-illumination-induced amorphization in electrically stressed BaTiO3, which is anisotropic, inhomogeneous and closely related with the field strength of applied voltage. Last, we show the effects of doping level on the dielectric response of La-doped or Cr-doped BaTiO3 nanocrystals. We expect our results to provide the bases for the overall understanding of the dielectric breakdown phenomenon and pave the way for the design and manufacture of future dielectric materials that operate reliably at higher voltages and higher efficiencies to meet the increasing demands for energy generation, storage, and transport. |