Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes.
Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes.
复制标题
二维 MoS2 薄片生长机制的直接 TEM 观察
DOI：
10.1038/ncomms12206
复制
发表时间：
2016-07-14
影响因子：
16.6
通讯作者：
Wang Y
中科院分区：
文献类型：
--
作者：
Fei L;Lei S;Zhang WB;Lu W;Lin Z;Lam CH;Chai Y;Wang Y
从微观上理解二维材料的生长机制对于可控合成功能纳米结构具有特别重要的意义。由于缺乏直接和有洞察力的观测，如何控制二维材料颗粒的取向和大小仍在争论中。在这里，我们用原位电子显微镜观察了硫代钼酸铵热分解过程中MoS_2薄片的形成阶段。在初始阶段(400℃)，垂直排列的MoS2结构以逐层模式生长。当温度升高到780℃时，MoS_2结构的取向变为水平。当生长温度达到850℃时，MoS_2的晶体尺寸通过合并相邻的片层而增大。我们的研究显示了MoS_2随着温度的变化而生长的直观观察，并为二维材料的可控取向和晶粒度提供了线索。
A microscopic understanding of the growth mechanism of two-dimensional materials is of particular importance for controllable synthesis of functional nanostructures. Because of the lack of direct and insightful observations, how to control the orientation and the size of two-dimensional material grains is still under debate. Here we discern distinct formation stages for MoS2 flakes from the thermolysis of ammonium thiomolybdates using in situ transmission electron microscopy. In the initial stage (400 °C), vertically aligned MoS2 structures grow in a layer-by-layer mode. With the increasing temperature of up to 780 °C, the orientation of MoS2 structures becomes horizontal. When the growth temperature reaches 850 °C, the crystalline size of MoS2 increases by merging adjacent flakes. Our study shows direct observations of MoS2 growth as the temperature evolves, and sheds light on the controllable orientation and grain size of two-dimensional materials.