CVD法生长二硫化钼原子层的微观机理研究

最近，利用化学气相沉积法（CVD）生长原子层厚度的二硫化钼受到了实验的广泛关注，然而离大规模可控生长高质量二维二硫化钼的目标仍然很远。从原子尺度理解其生长机理可以发现其中的规律，从而控制反应条件，为进一步制备高质量的样品提供指导。本项目基于我们前期对单层二硫化钼与二维衬底之间不同相互作用机制的理解，结合第一性原理和分子动力学计算，模拟前体的分解、活性基团在表面的扩散迁移及其与硫的氧化还原反应、聚集成核等生长过程，进一步研究生长过程中晶界等缺陷形成的动力学行为及其对电子和光学性质的影响。我们将着重探讨芳香分子促进成核的物理机制，寻找潜在的能促进成核的分子，并探索实验方法的改进以提高样品质量。本项目从原子尺度研究二维二硫化钼的生长过程，所得的结果可以为控制反应条件来制备高质量样品提供理论指导。

Chemical vapor deposition (CVD) is potentially a prevailing technique for large scale and controlled production of two-dimensional (2D) MoS2, Nevertheless, the current CVD technology is still far away from the targeted controlled production of high quality 2D MoS2. An improved understanding of the growth mechanism of 2D MoS2 at the atomic level would shed new lights on the intrinsic growth rules and offer insightful guidance for experimental synthesis. Based on our previous comprehensive study of interactions between 2D MoS2 and different 2D substrates, we plan to use the first-principle calculations combined with molecular dynamic simulations to simulate the growth process of 2D MoS2 under various reaction conditions, including dissociation of precursors, diffusion of active species, the redox reactions with S. Our goal is to reveal CVD nucleation mechanism for 2D MoS2 growing on different substrates. The effect of grain boundary on the electronic and optic properties will be explored. More importantly, positive effects of the aromatic molecules to the nucleation will especially be investigated. New insights and intrinsic rules gained on the growth mechanism of 2D MoS2 will assist experimentalists to develop new CVD technology for grow high-quality 2D MoS2 in a controllable manner.