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The scalable preparation of high-quality and low-cost two-dimensional (2D) materials is critical to achieving their potential applications in various fields. Chemical vapor deposition (CVD) method is considered the most promising method for producing ultrathin 2D materials and has continued to develop in recent years. First-principles calculations have provided important theoretical guidance for the CVD synthesis of 2D materials, and have played an increasingly important role in the field of material synthesis in recent years.In this review, we present recent advances in the growth mechanism of 2D materials, focusing on the theoretical research progress of four typical 2D materials: graphene, hexagonal boron nitride (hBN), transition metal dichalcogenide (TMDC), and phosphorene. Several aspects of the growth process are discussed in detail, including the decomposition of precursors, nucleation, growth kinetics, domain shape, and epitaxial and alignment of 2D crystals. Based on the understanding of these atomic-scale growth processes, strategies toward the wafer-scale growth of continuous and homogeneous 2D thin films are proposed and confirmed by experiments. In the final section, we summarize future challenges and opportunities in the computational studies of the growth mechanism of 2D materials.

In this paper, a metamaterial absorber is proposed, which is constructed by graphene rings and a gold film separated by an ultrathin S i O 2 layer. The feature of this absorber is that the absorption bands can be adjusted either by applying external electric fields or by rotating the polarization angles of the incident electromagnetic waves. The calculation results show that the continuous tunable or two- to multi-band absorptions can be realized by the above two methods. Through equivalent medium theory and impedance-matching condition, the anisotropic absorption mechanism of this absorber is explained. Moreover, the simple specific design makes the absorption bands able to be further tuned by adjusting various parameters, such as the geometry sizes and relaxation times of graphene rings. Our results indicate that the absorber has great adjustability and great potential application in filtering, terahertz signal detection, signal parameter estimation, smart sensing, tunable absorbers, and cloaking.