Atomic electrostatic maps of 1D channels in 2D semiconductors using 4D scanning transmission electron microscopy
Atomic electrostatic maps of 1D channels in 2D semiconductors using 4D scanning transmission electron microscopy
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DOI：
10.1038/s41467-019-08904-9
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发表时间：
2019-03-08
影响因子：
16.6
通讯作者：
Warner, Jamie H.
中科院分区：
文献类型：
--
作者：
Fang, Shiang;Wen, Yi;Warner, Jamie H.
材料中的缺陷引起静电场的波动，反映了局部电荷密度，但用单原子灵敏度成像是具有挑战性的。然而，如果可能的话，这提供了关于吸附原子结合的能量学、局部传导通道、分子功能及其与各个键的关系的信息。在这里，超稳定电子光学与高速2D电子检测器相结合，使用4D扫描透射电子显微镜在2D单层中绘制单个原子周围的静电场。同时成像的电场，相位，环形暗场和总电荷在2D二硫化钼和WS2的原始区域和区域与1D线证明。硫线空位中的间隙状态导致1D富电子通道，其通过实验映射并使用密度泛函理论计算确认。我们展示了静电场是如何在有缺陷的地区敏感的原子键合和结构确定的变化超出常规成像。
Defects in materials give rise to fluctuations in electrostatic fields that reflect the local charge density, but imaging this with single atom sensitivity is challenging. However, if possible, this provides information about the energetics of adatom binding, localized conduction channels, molecular functionality and their relationship to individual bonds. Here, ultrastable electronoptics are combined with a high-speed 2D electron detector to map electrostatic fields around individual atoms in 2D monolayers using 4D scanning transmission electron microscopy. Simultaneous imaging of the electric field, phase, annular dark field and the total charge in 2D MoS2 and WS2 is demonstrated for pristine areas and regions with 1D wires. The in-gap states in sulphur line vacancies cause 1D electron-rich channels that are mapped experimentally and confirmed using density functional theory calculations. We show how electrostatic fields are sensitive in defective areas to changes of atomic bonding and structural determination beyond conventional imaging.