Demonstrative operation of four-terminal memristive devices fabricated on reduced TiO2 single crystals
Demonstrative operation of four-terminal memristive devices fabricated on reduced TiO2 single crystals
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DOI：
10.1038/s41598-018-38347-z
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发表时间：
2019-02
影响因子：
4.6
通讯作者：
S. Takeuchi;T. Shimizu;T. Isaka;T. Tohei;N. Ikarashi;A. Sakai
中科院分区：
文献类型：
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作者：
S. Takeuchi;T. Shimizu;T. Isaka;T. Tohei;N. Ikarashi;A. Sakai
在还原 TiO2(TiO2−x) 单晶基板上制造的四端子平面忆阻器件中演示了电阻开关 (RS)。在该装置中，一对对角相对的电极端子用于改变另一对对角相对的电极端子之间的区域中的氧空位的分布。这允许基于电着色对氧空位分布进行显微目视观察。在 TiO2−x 中观察到的视觉对比度反映了器件电活性区中的氧空位浓度，可以通过向电极施加各种外部电压来修改氧空位浓度。器件中流动的电流很大程度上取决于修改后的氧空位分布，并且当所施加的外部电压的极化反转时，所产生的电阻是可切换的。 TiO2−x 基底的晶体取向对可逆 RS 现象有很大影响。借助对器件电活性区晶体和电子结构的微观分析，详细阐述了电压驱动电阻变化背后的机制。抑制由积累的氧空位组成的不可逆导电结构的形成是在器件中建立可逆RS的关键。
Resistive switching (RS) was demonstrated in four-terminal planar memristive devices fabricated on reduced TiO2(TiO2−x) single crystal substrates. In the device, a pair of diagonally opposing electrode terminals is used to modify the distribution of oxygen vacancies in the region between another pair of diagonally opposing electrode terminals. This allowed microscopic visual observations of the oxygen vacancy distribution based on electrocoloring. The visual contrast observed in the TiO2−xreflects the oxygen vacancy concentration in the electrically active zone of the device, which can be modified by application of various external voltages to the electrodes. The current that flows in the device is significantly dependent on the modified oxygen vacancy distribution and the resultant resistance is switchable when the polarization of the applied external voltage is reversed. The crystallographic orientation of the TiO2−xsubstrate has a strong influence on the reversible RS phenomenon. Mechanisms behind the voltage-driven resistance change are elaborated with the aid of microscopic analysis for both crystalline and electronic structures in the electrically active zone of the device. Suppression of the formation of irreversible conductive structures comprised of accumulated oxygen vacancies is a key to establishing reversible RS in the device.