Hefei National Laboratory for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science & Technology of China , Hefei, Anhui 230026, P. R. China.
J Am Chem Soc. 2015 Mar 4;137(8):3102-8. doi: 10.1021/jacs.5b00021. Epub 2015 Feb 19.
On the road of innovation in modern information technology, resistive switching random access memory (RRAM) has been considered to be the best potential candidate to replace the conventional Si-based technologies. In fact, the key prerequisite of high storage density and low power consumption as well as flexibility for the tangible next generation of nonvolatile memories has stimulated extensive research into RRAM. Herein, we highlight an inorganic graphene analogue, ultrathin WO3·H2O nanosheets with only 2-3 nm thickness, as a promising material to construct a high performance and flexible RRAM device. The abundant vacancy associates in the ultrathin nanosheets, revealed by the positron annihilation spectra, act not only carrier reservoir to provide carriers but also capture center to trap the actived Cu(2+) for the formation of conductive filaments, which synergistically realize the resistive switching memory with low operating voltage (+1.0 V/-1.14 V) and large resistance ON/OFF ratio (>10(5)). This ultrathin-nanosheets-based RRAM device also shows long retention time (>10(5) s), good endurance (>5000 cycles), and excellent flexibility. The finding of the existence of distinct defects in ultrathin nanosheets undoubtedly leads to an atomic level deep understanding of the underlying nature of the resistive switching behavior, which may serve as a guide to improve the performances and promote the rapid development of RRAM.
在现代信息技术的创新之路上，阻变随机存取存储器（RRAM）被认为是替代传统硅基技术的最佳潜在候选者。事实上，高存储密度、低功耗以及灵活性等关键前提条件，刺激了人们对 RRAM 的广泛研究，以期成为下一代的有形非易失性存储器。在此，我们重点介绍了一种无机石墨烯类似物，即具有仅 2-3nm 厚度的超薄 WO3·H2O 纳米片，其有望作为构建高性能和柔性 RRAM 器件的材料。正电子湮没谱揭示了超薄纳米片中丰富的空位，这些空位不仅可以作为载流子储存库来提供载流子，还可以作为捕获中心来捕获活性 Cu(2+)以形成导电细丝，从而协同实现具有低工作电压（+1.0V/-1.14V）和大 ON/OFF 电阻比（>10(5)）的阻变存储。基于这种超薄纳米片的 RRAM 器件还具有长保持时间（>10(5)s）、良好的耐久性（>5000 次循环）和出色的柔韧性。超薄纳米片中存在明显缺陷的发现，无疑为阻变开关行为的潜在本质提供了原子级别的深入理解，这可能为提高性能和推动 RRAM 的快速发展提供指导。
