Direct Observations of Field-Intensity-Dependent Dielectric Breakdown Mechanisms in TiO2 Single Nanocrystals

Tian, Xinchun
Brennecka, Geoff
Tan, Xiaoli
Tan, Xiaoli
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Tan, Xiaoli
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One of the main challenges for next-generation electric power systems and electronics is to avoid premature dielectric breakdown in insulators and capacitors and to ensure reliable operations at higher electric fields and higher efficiencies. However, dielectric breakdown is a complex phenomenon and often involves many different processes simultaneously. Here we show distinctly different defect-related and intrinsic breakdown processes by studying individual, single-crystalline TiO2 nanoparticles using in situ transmission electron microscopy (TEM). As the applied electric field intensity rises, rutile-to-anatase phase transition, local amorphization/melting, and ablation are identified as the corresponding breakdown processes, the field intensity thresholds of which are found to be related to the position of the intensified field and the duration of the applied bias relative to the time of charged defects accumulation. Our observations reveal an intensity-dependent dielectric response of crystalline oxides at breakdown and suggest possible routes to suppress the initiation of premature dielectric breakdown. Hence, they will aid the design and development of next-generation robust and efficient solid dielectrics.

<p>This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in <em>ACS Nano</em>, copyright © American Chemical Society after peer review. To access the final edited and published work see DOI: <a href="" target="_blank">10.1021/acsnano.0c02346</a>. Posted with permission.</p>
TiO2 nanocrystal, dielectric breakdown, in situ biasing TEM, oxygen vacancy, phase transition