Sarkar Soumya, Han Zirun, Ghani Maheera Abdul, Strkalj Nives, Kim Jung Ho, Wang Yan, Jariwala Deep, Chhowalla Manish
Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom.
Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Nano Lett. 2024 Oct 23;24(42):13232-13237. doi: 10.1021/acs.nanolett.4c03360. Epub 2024 Oct 9.
Some van der Waals (vdW) materials exhibit ferroelectricity, making them promising for novel nonvolatile memories (NVMs) such as ferroelectric diodes (FeDs). CuInPS (CIPS) is a well-known vdW ferroelectric that has been integrated with graphene for memory devices. Here we demonstrate FeDs with self-rectifying, hysteretic current-voltage characteristics based on vertical heterostructures of 10 nm thick CIPS and graphene. By using vdW indium-cobalt top electrodes and graphene bottom electrodes, we achieve a high electroresistance (on- and off-state resistance ratios) of ∼10, an on-state rectification ratio of 2500 for read/write voltages of 2 V/0.5 V, and a maximum output current density of 100 A/cm. These metrics compare favorably with state-of-the-art FeDs. Piezoresponse force microscopy measurements show that stabilization of intermediate net polarization states in CIPS leads to stable multibit data retention at room temperature. The combination of two-terminal design, multibit memory, and low-power operation in CIPS-based FeDs is potentially interesting for compute-in-memory and neuromorphic computing applications.
一些范德华（vdW）材料表现出铁电性，这使得它们在诸如铁电二极管（FeD）等新型非易失性存储器（NVM）方面具有潜力。铜铟磷硫（CIPS）是一种著名的vdW铁电体，已与石墨烯集成用于存储器件。在此，我们展示了基于10纳米厚的CIPS和石墨烯的垂直异质结构的具有自整流、滞后电流-电压特性的FeD。通过使用vdW铟钴顶部电极和石墨烯底部电极，我们实现了约10的高电阻（开态和关态电阻比）、对于2 V/0.5 V的读/写电压2500的开态整流比以及100 A/cm²的最大输出电流密度。这些指标与最先进的FeD相比具有优势。压电力显微镜测量表明，CIPS中中间净极化状态的稳定导致在室温下稳定的多位数据保持。基于CIPS的FeD中的两端设计、多位存储和低功耗操作的结合对于内存计算和神经形态计算应用可能具有潜在的吸引力。
