Zhou Si, Wang Shanshan, Li Huashan, Xu Wenshuo, Gong Chuncheng, Grossman Jeffrey C, Warner Jamie H
Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, U.K.
Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
ACS Omega. 2017 Jul 7;2(7):3315-3324. doi: 10.1021/acsomega.7b00734. eCollection 2017 Jul 31.
We present a detailed atomic-level study of defects in bilayer MoS using aberration-corrected transmission electron microscopy at an 80 kV accelerating voltage. Sulfur vacancies are found in both the top and bottom layers in 2H- and 3R-stacked MoS bilayers. In 3R-stacked bilayers, sulfur vacancies can migrate between layers but more preferably reside in the (Mo-2S) column rather than the (2S) column, indicating more complex vacancy production and migration in the bilayer system. As the point vacancy number increases, aggregation into larger defect structures occurs, and this impacts the interlayer stacking. Competition between compression in one layer from the loss of S atoms and the van der Waals interlayer force causes much less structural deformations than those in the monolayer system. Sulfur vacancy lines neighboring in top and bottom layers introduce less strain compared to those staggered in the same layer. These results show how defect structures in multilayered two-dimensional materials differ from their monolayer form.
我们利用80 kV加速电压下的像差校正透射电子显微镜，对双层MoS中的缺陷进行了详细的原子级研究。在2H和3R堆叠的MoS双层的顶层和底层都发现了硫空位。在3R堆叠的双层中，硫空位可以在层间迁移，但更倾向于存在于（Mo-2S）柱而不是（2S）柱中，这表明双层体系中空位的产生和迁移更为复杂。随着点空位数量的增加，会聚集形成更大的缺陷结构，这会影响层间堆叠。一层中由于S原子损失导致的压缩与范德华层间力之间的竞争，所引起的结构变形比单层体系中的要小得多。与同一层中交错排列的硫空位线相比，顶层和底层相邻的硫空位线引入的应变较小。这些结果表明了多层二维材料中的缺陷结构与其单层形式有何不同。
