Stacking Faults and Intercalants in (Ta1-xTix)Se2 Revealed by Cross-Sectional Transmission Electron Microscopy
Stacking Faults and Intercalants in (Ta1-xTix)Se2 Revealed by Cross-Sectional Transmission Electron Microscopy
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截面透射电子显微镜揭示 (Ta1-xTix)Se2 中的堆垛层错和嵌入剂
DOI：
10.1021/acs.jpcc.2c03943
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发表时间：
2022
影响因子：
3.7
通讯作者：
Kazuhisa Sato and Toshiya Matsushita
中科院分区：
文献类型：
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作者：
Kazuhisa Sato and Toshiya Matsushita
用化学灵敏的高角度环形暗场扫描电子显微镜(HAADFSTEM)截面观察研究了具有电导率各向异性特征的层状化合物(Ta1-xTix)Se2(0≤x≤1)中的结构缺陷。无论晶体生长后的钛含量(TiSe2除外)或热历史如何，在范德华(VDW)能隙中Se原子之间的最宽空间内都检测到了插层剂。同时具有3R和2H结构的二元TaSe2具有高密度的层错，而添加Ti则稳定了1T结构，没有层错。结果表明，(TA1-xTix)Se2化合物的结构缺陷主要是由化学成分决定的。Ta与Ti的取代起到空穴添加的作用，减少了层中的传导电子数，而VDW禁带中的插层原子可能不起到传导电子的施主作用。
Structural defects in the layered compounds (Ta1–xTix)Se2(0 ≤x≤ 1), characterized by anisotropy in electrical conductivity, have been studied by cross-sectional observation using chemically sensitive high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Intercalants were detected in the widest space between Se atoms across the van der Waals (vdW) gap, regardless of the Ti content (except TiSe2) or thermal history after the crystal growth. Binary TaSe2with both 3Rand 2Hstructures includes a high density of stacking faults, while Ti addition stabilizes the 1Tstructure with no stacking faults. We show that the chemical composition dominates the structural defects in the (Ta1–xTix)Se2compounds. Substitution of Ta with Ti acts as a hole addition, which reduces the number of conduction electrons in the layer, while an intercalated atom in the vdW gap may not act as a donor of conduction electrons.