Mechanically tuned conductivity at individual grain boundaries in polycrystalline ZnO varistor ceramics
Mechanically tuned conductivity at individual grain boundaries in polycrystalline ZnO varistor ceramics
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DOI：
10.1063/1.5131003
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发表时间：
2020-01
影响因子：
3.2
通讯作者：
Daniel Bremecker;P. Keil;M. Gehringer;Daniel Isaia;J. Rödel;T. Frömling
中科院分区：
文献类型：
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作者：
Daniel Bremecker;P. Keil;M. Gehringer;Daniel Isaia;J. Rödel;T. Frömling
在过去的十年中，机械引起的电性能变化获得了越来越多的关注。研究领域压电电子学，它描述了势垒高度的变化（例如，在肖特基接触）的压电电荷，可能会导致有前途的应用，如传感器或应变晶体管。在这方面的贡献，在多晶ZnO的晶界的机械应力的势垒的变化已被量化。通过同时测量两个相邻晶粒的晶体取向来提供结晶化。势垒高度的最大变化可以观察到在ZnO-ZnO晶界表现出压敏电阻性能。在这种情况下，势垒高度几乎可以完全由正压电电荷降低。此外，观察到的势垒高度的增加与负压电电荷。所开发的物理模型表明，外部施加的电压和诱导的正压电电荷的屏障性能的等效影响。反过来，不仅势垒高度被压电电荷修改，而且击穿电压。然而，这只是在实验中得到了间接的证实。这使得所提出的模型合理化。此外，统计研究揭示了压敏电阻陶瓷的击穿电压分布随应力条件的变化而变化。在过去的十年中，机械引起的电性能变化引起了越来越多的关注。研究领域压电电子学，它描述了势垒高度的变化（例如，在肖特基接触）的压电电荷，可能会导致有前途的应用，如传感器或应变晶体管。在这方面的贡献，在多晶ZnO的晶界的机械应力的势垒的变化已被量化。通过同时测量两个相邻晶粒的晶体取向来提供结晶化。势垒高度的最大变化可以观察到在ZnO-ZnO晶界表现出压敏电阻性能。在这种情况下，势垒高度几乎可以完全由正压电电荷降低。此外，观察到的势垒高度的增加与负压电电荷。所开发的物理模型表明，外部施加的电压和诱导的正压电效应的等效影响。
Mechanically induced changes in electrical properties have gained increasing interest over the last decade. The research field piezotronics, which describes the change in potential barrier height (e.g., at Schottky contacts) by piezoelectric charges, could lead to promising applications such as sensors or strain trigged transistors. In this contribution, the changes of potential barriers by mechanical stress at several grain boundaries of polycrystalline ZnO have been quantified. Rationalization is provided by concurrent measurement of crystal orientations of both neighboring grains. The highest changes in barrier height could be observed at ZnO–ZnO grain boundaries exhibiting varistor properties. In this case, the barrier height can be almost completely reduced by positive piezoelectric charges. Furthermore, an increase in barrier height is observed with negative piezoelectric charges. The developed physical model suggests an equivalent impact of externally applied voltage and induced positive piezoelectric charge on the barrier properties. In turn, not only the barrier height is modified by piezoelectric charges but also the breakdown voltage. This has, nevertheless, been only indirectly verified in experiments. These allow rationalizing the proposed model. Furthermore, a statistical study reveals a change in the distribution of breakdown voltages with changing stress conditions in the varistor ceramic.Mechanically induced changes in electrical properties have gained increasing interest over the last decade. The research field piezotronics, which describes the change in potential barrier height (e.g., at Schottky contacts) by piezoelectric charges, could lead to promising applications such as sensors or strain trigged transistors. In this contribution, the changes of potential barriers by mechanical stress at several grain boundaries of polycrystalline ZnO have been quantified. Rationalization is provided by concurrent measurement of crystal orientations of both neighboring grains. The highest changes in barrier height could be observed at ZnO–ZnO grain boundaries exhibiting varistor properties. In this case, the barrier height can be almost completely reduced by positive piezoelectric charges. Furthermore, an increase in barrier height is observed with negative piezoelectric charges. The developed physical model suggests an equivalent impact of externally applied voltage and induced positive piezoelect...