College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Suzhou Nano Science and Technology, National United Engineering Laboratory of Functionalized Environmental Adsorption Materials, Soochow University, Suzhou, 215123, P. R. China.
Testing and Analysis Center, Soochow University, Suzhou, 215123, P. R. China.
Adv Mater. 2019 Sep;31(37):e1806424. doi: 10.1002/adma.201806424. Epub 2019 Aug 5.
Memcapacitors are emerging as an attractive candidate for high-density information storage due to their multilevel and adjustable capacitances and long-term retention without a power supply. However, knowledge of their memcapacitive mechanism remains unclear and accounts for the limited implementation of memcapacitors for multilevel memory technologies. Here, repeatable and reproducible quaternary memories fabricated from hybrid perovskite (CH NH SnBr ) memcapacitors are reported. The device can be modulated to at least four capacitive states ranging from 0 to 169 pF with retention for 10 s. Impressively, an effective device yield approaching 100% for quaternary memory switching is achieved by a batch of devices; each state has a sufficiently narrow distribution that can be distinguished from the others and is superior to most multilevel memories that have a low device yield as well as an overlapping distribution of states. The memcapacitive switching stems from the modulated p-i-n junction capacitance triggered by Br migration, as demonstrated by in situ element mapping, X-ray photoelectron spectra, and frequency-dependent capacitance measurements; this mechanism is different from the widely reported memristive switching involving filamentary conduction. The results provide a new way to produce high-density information storage through memcapacitors.
忆阻器作为高密度信息存储的候选者，由于其具有多级可调电容和无需电源即可长期保持的特点而备受关注。然而，其记忆机制仍不清楚，这也限制了忆阻器在多级存储技术中的应用。本文报道了一种基于钙钛矿（CH3NH3SnBr3）忆阻器的可重复、可再现的四进制存储器。该器件可调制到至少四个电容状态，电容范围从 0 到 169 pF，保持时间为 10 s。令人印象深刻的是，通过一批器件实现了接近 100%的有效器件产量，用于四进制存储切换；每个状态的分布都足够窄，可以与其他状态区分开来，优于大多数具有低器件产量和状态分布重叠的多级存储器。忆阻开关源于 Br 迁移触发的调制 p-i-n 结电容，这可以通过原位元素映射、X 射线光电子能谱和频率相关电容测量来证明；这种机制与广泛报道的涉及丝状导电机理的忆阻开关不同。研究结果为通过忆阻器实现高密度信息存储提供了一种新方法。
