Nikam Revannath Dnyandeo, Rajput Krishn Gopal, Hwang Hyunsang
Center for Single Atom-based Semiconductor Device, Department of Material Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Republic of Korea.
Small. 2021 Feb;17(7):e2006760. doi: 10.1002/smll.202006760. Epub 2021 Jan 27.
The first report of a quantized conductance atomic threshold switch (QCATS) using an atomically-thin hexagonal boron nitride (hBN) layer is provided. This QCATS has applications in memory and logic devices. The QCATS device shows a stable and reproducible conductance quantization state at 1·G by forming single-atom point contact through a monoatomic boron defect in an hBN layer. An atomistic switching mechanism in hBN-QCATS is confirmed by in situ visualization of mono-atomic conductive filaments. Atomic defects in hBN are the key factor that affects the switching characteristic. The hBN-QCATS has excellent switching characteristics such as low operation voltage of 0.3 V, low "off" current of 1 pA, fast switching of 50 ns, and high endurance > 10 cycles. The variability of switching characteristics, which are the major problems of switching device, can be solved by reducing the area and thickness of the switching region to form single-atom point contact. The switching layer thickness is scaled down to the single-atom (≈0.33 nm) h-BN layer, and the switching area is limited to single-atom defects. By implementing excellent switching characteristics using single-layer hBN, the possibility of implementing stable and uniform atomic-switching devices for future memory and logic applications is confirmed.
首次报道了一种使用原子级薄的六方氮化硼（hBN）层的量子化电导原子阈值开关（QCATS）。这种QCATS在存储器和逻辑器件中有应用。通过在hBN层中通过单原子硼缺陷形成单原子点接触，该QCATS器件在1·G时显示出稳定且可重复的电导量子化状态。通过单原子导电细丝的原位可视化证实了hBN-QCATS中的原子开关机制。hBN中的原子缺陷是影响开关特性的关键因素。hBN-QCATS具有优异的开关特性，如0.3 V的低工作电压、1 pA的低“关”电流、50 ns的快速开关以及大于10次循环的高耐久性。开关特性的可变性是开关器件的主要问题，通过减小开关区域的面积和厚度以形成单原子点接触可以解决。开关层厚度缩小到单原子（≈0.33 nm）的h-BN层，并且开关区域限于单原子缺陷。通过使用单层hBN实现优异的开关特性，证实了为未来的存储器和逻辑应用实现稳定且均匀的原子开关器件的可能性。
