Synergistic Resistive Switching Mechanism of Oxygen Vacancies and Metal Interstitials in Ta2O5

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• 作者：Linggang Zhu ; Jian Zhou ; Zhonglu Guo ; Zhimei Sun
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 4, 2016
• 年：2016
• 卷：120
• 期：4
• 页码：2456-2463
• 全文大小：506K
• ISSN：1932-7455

文摘

Ta₂O₅ is extensively studied as a data-storage material for resistance random access memory (RRAM). The resistive switching (RS) in Ta₂O₅-based RRAM is generally believed to be due to the diffusion of oxygen vacancy (Vo) inside the oxide, while the role of metal interstitials is paid less attention. Here, on the basis of first-principles calculations, we show that the role of interstitial Ta (Ta_i) is competitive under the oxygen-poor condition and should also contribute to RS in Ta₂O₅. This is obvious by our calculated comparable energy barriers for the diffusion of Vo and Ta_i, which are 3.5 and 3.7 eV, respectively. Furthermore, the presence of electric field in working devices will enhance the migration of Ta_i due to its higher charge states compared to Vo. Meanwhile, Ta_i will introduce more defect states closer to the conduction bands and, thus, is more effective on tuning the electronic structure of Ta₂O₅. The present work unravels the contribution of Ta cations in RS of tantalum oxide-based RRAM, presenting a synergistic RS mechanism of oxygen vacancies and metal interstitials, which should be helpful for optimizing and designing novel RRAM devices.