Mo Concentration Controls the Morphological Transitions from Dendritic to Semicompact, and to Compact Growth of Monolayer Crystalline MoS2 on Various Substrates
Mo Concentration Controls the Morphological Transitions from Dendritic to Semicompact, and to Compact Growth of Monolayer Crystalline MoS2 on Various Substrates
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Mo 浓度控制各种基底上单层晶体 MoS2 从枝晶到半致密以及致密生长的形态转变
DOI：
10.1021/acsami.9b14577
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发表时间：
2019
影响因子：
9.5
通讯作者：
Dou Ruifen
中科院分区：
文献类型：
--
作者：
Li Xiaying;Zhang Shiping;Chen Shuai;Zhang Xingli;Gao Junfeng;Zhang Yong-Wei;Zhao Jijun;Shen Xi;Yu Richeng;Yang Yu;He Lin;Nie Jiacai;Xiong Changmin;Dou Ruifen
过渡金属二硫属化合物（TMDC）生长中的畴形态大多为三角形，很少为树枝状。在这里，我们报告了一个强大的化学气相沉积方法来制造原子薄的2 H相MoS 2枝晶在几个单晶基板上具有不同的晶格结构，如金红石-TiO 2（001），SrTiO 3（001），蓝宝石（0001）。研究发现，通过调节Mo原子的浓度，在低Mo浓度下，MoS 2畴的形貌由三齿枝晶转变为中等Mo浓度下的半致密分形畴，而在高Mo浓度下，MoS 2畴的形貌由三角形转变为致密的三角形.第一性原理计算表明，边缘扩散障碍的Mo是可比的附着障碍，抑制快速Mo原子扩散沿着边缘。动力学Monte Carlo模拟与不同的Mo浓度很好地再现了实验结果。实验和理论分析表明，在低Mo浓度下，MoS 2枝晶畴的生长是一个非平衡过程，并受Mo原子吸附动力学的控制.我们的研究提出了一种有效的途径来控制TMDCs的形态，通过简单地调整过渡金属吸附原子的浓度。
The domain morphology in the growth of transition-metal dichalcogenides (TMDCs) is mostly triangular but rarely dendritic. Here, we report a robust chemical vapor deposition method to fabricate atomic-thin 2H-phase MoS2dendrites on several single-crystalline substrates with different lattice structures, such as rutile-TiO2(001), SrTiO3(001), and sapphire(0001). It is found that by tuning the concentration of Mo adatoms, the morphology of MoS2domains on these substrates evolves from tridentate dendrites at a low Mo concentration to semicompact fractal domains at an intermediate Mo concentration, and to a compact triangular shape at a high Mo concentration. First-principles calculations reveal that the edge diffusion barrier of Mo is comparable to the attachment barrier, inhibiting fast Mo atom diffusion along the edge. Kinetics Monte Carlo simulations with varying Mo concentrations well reproduce the experimental results. Our combined experimental and theoretical analyses evidently show that the growth of MoS2dendritic domains at a low Mo concentration is a nonequilibrium process, which is dominated by the kinetics of Mo adatoms. Our study presents an effective route to control the morphology of TMDCs by simply tuning the transition-metal adatom concentration.