Preferential S/Se occupation in an anisotropic ReS2(1-x)Se2x monolayer alloy
Preferential S/Se occupation in an anisotropic ReS2(1-x)Se2x monolayer alloy
复制标题
各向异性 ReS2(1-x)Se2x 单层合金中 S/Se 的优先占据
DOI：
10.1039/c7nr05289h
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发表时间：
2017
期刊：
影响因子：
6.7
通讯作者：
Xie Liming
中科院分区：
文献类型：
--
作者：
Wen Wen;Lin Junhao;Suenaga Kazu;Guo Yuzheng;Zhu Yiming;Hsu Hung Pin;Xie Liming
二维金属二硫族化合物（TMDs）的能带结构工程对其光-物质相互作用和光电子应用至关重要。在tmd中合金化具有不同化学计量的不同金属或硫元素，为调制二维材料的电子结构和性能提供了一种通用而有效的方法。在二维合金中，原子的空间分布和局部配位的量化有助于在原子尺度上建立结构-性能关系。本文利用扫描透射电镜（STEM）对各向异性ReS1.4Se0.6中硫和硒原子的原子构型进行了成像和分析。在z对比图像中，我们实现了Re、Se和S在不同配位位点的识别和定量。与MoS2(1−x)Se2x和Mo1−xWxS2中金属元素和硫元素的随机分布不同，我们发现在ReS2(1−x)Se2x中Se原子优先位于Re4钻石内部。进一步的密度泛函理论（DFT）计算揭示了硒在不同位置占据的电子结构调制。
Band structure engineering of two-dimensional (2D) metal dichalcogenides (TMDs) is crucial for their light–matter interaction and optoelectronic applications. Alloying of different metal or chalcogen elements with different stoichiometries in TMDs provides a versatile and efficient approach for modulating the electronic structure and properties of 2D materials. In 2D alloys, quantification of spatial distribution and local coordination of atoms facilitates the establishment of the structure–property relationship at the atomic scale. Here, we have imaged and analyzed the atomic configuration of sulfur and selenium atoms in anisotropic ReS1.4Se0.6 by scanning transmission electron microscopy (STEM). In Z-contrast images, we have realized the identification and quantification of Re, Se and S at different coordination sites. Different from the random distribution of metal and chalcogen elements in MoS2(1−x)Se2x and Mo1−xWxS2, we find that Se atoms preferentially locate inside of Re4 diamonds in ReS2(1−x)Se2x. Further density function theory (DFT) calculations reveal electronic structure modulation for Se occupation at different sites.