Microelectronics Research Center, University of Texas at Austin, Austin, TX, 78758, USA.
Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, Tainan, 701, Taiwan.
Adv Mater. 2019 Apr;31(15):e1806790. doi: 10.1002/adma.201806790. Epub 2019 Feb 17.
2D materials have attracted much interest over the past decade in nanoelectronics. However, it was believed that the atomically thin layered materials are not able to show memristive effect in vertically stacked structure, until the recent discovery of monolayer transition metal dichalcogenide (TMD) atomristors, overcoming the scaling limit to sub-nanometer. Herein, the nonvolatile resistance switching (NVRS) phenomenon in monolayer hexagonal boron nitride (h-BN), a typical 2D insulator, is reported. The h-BN atomristors are studied using different electrodes and structures, featuring forming-free switching in both unipolar and bipolar operations, with large on/off ratio (up to 10 ). Moreover, fast switching speed (<15 ns) is demonstrated via pulse operation. Compared with monolayer TMDs, the one-atom-thin h-BN sheet reduces the vertical scaling to ≈0.33 nm, representing a record thickness for memory materials. Simulation results based on ab-initio method reveal that substitution of metal ions into h-BN vacancies during electrical switching is a likely mechanism. The existence of NVRS in monolayer h-BN indicates fruitful interactions between defects, metal ions and interfaces, and can advance emerging applications on ultrathin flexible memory, printed electronics, neuromorphic computing, and radio frequency switches.
二维材料在过去十年的纳米电子学中引起了广泛关注。然而，人们曾认为，原子层状材料在垂直堆叠结构中无法表现出忆阻效应，直到最近发现单层过渡金属二卤化物（TMD）原子晶体管，才克服了亚纳米级的缩放限制。在此，报道了典型二维绝缘体单层六方氮化硼（h-BN）中的非易失性电阻开关（NVRS）现象。使用不同的电极和结构研究了 h-BN 原子晶体管，其具有在单极和双极操作中均无需形成即可切换的特点，具有较大的导通/关断比（高达 10）。此外，通过脉冲操作证明了快速的开关速度（<15 ns）。与单层 TMD 相比，单层 h-BN 片将垂直缩放降低至 ≈0.33nm，代表了存储材料的记录厚度。基于第一性原理方法的模拟结果表明，在电切换过程中金属离子取代 h-BN 空位是一种可能的机制。单层 h-BN 中的 NVRS 表明缺陷、金属离子和界面之间存在有益的相互作用，并且可以推进在超薄柔性存储、印刷电子、神经形态计算和射频开关等新兴应用。
