Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208, United States.
Materials Science and Engineering Division, National Institute of Standards and Technology , 100 Bureau Drive, Gaithersburg, Maryland 20899, United States.
Nano Lett. 2016 Oct 12;16(10):6064-6069. doi: 10.1021/acs.nanolett.6b02104. Epub 2016 Sep 9.
Impurity doping in two-dimensional (2D) materials can provide a route to tuning electronic properties, so it is important to be able to determine the distribution of dopant atoms within and between layers. Here we report the tomographic mapping of dopants in layered 2D materials with atomic sensitivity and subnanometer spatial resolution using atom probe tomography (APT). APT analysis shows that Ag dopes both BiSe and PbSe layers in (PbSe)(BiSe), and correlations in the position of Ag atoms suggest a pairing across neighboring BiSe and PbSe layers. Density functional theory (DFT) calculations confirm the favorability of substitutional doping for both Pb and Bi and provide insights into the observed spatial correlations in dopant locations.
杂质掺杂二维（2D）材料可以提供一种调节电子性质的途径，因此能够确定掺杂原子在层内和层间的分布是很重要的。在这里，我们使用原子探针断层成像术（APT）报告了具有原子灵敏度和亚纳米空间分辨率的层状 2D 材料中掺杂剂的断层成像映射。APT 分析表明，Ag 掺杂（PbSe）（BiSe）中的 BiSe 和 PbSe 层，Ag 原子位置的相关性表明相邻的 BiSe 和 PbSe 层之间存在配对。密度泛函理论（DFT）计算证实了 Pb 和 Bi 的替代掺杂的有利性，并提供了对观察到的掺杂位置空间相关性的深入了解。
