化学学报 ›› 2022, Vol. 80 ›› Issue (4): 510-516.DOI: 10.6023/A21110533 上一篇    下一篇

研究论文

二维单层MoSi2X4 (X=N, P, As)的电子结构及光学性质研究

龚雪a, 马新国a,b,*(), 万锋达a, 段汪洋a, 杨小玲a,b, 朱进容a,b   

  1. a 湖北工业大学芯片产业学院 武汉 430068
    b 湖北省能源光电器件与系统工程技术研究中心 武汉 430068
  • 投稿日期:2021-11-24 发布日期:2022-04-28
  • 通讯作者: 马新国
  • 基金资助:
    国家自然科学基金(51472081)

Study on the Electronic Structure and Optical Properties of Two-dimensional Monolayer MoSi2X4 (X=N, P, As)

Xue Gonga, Xinguo Maa,b(), Fengda Wana, Wangyang Duana, Xiaoling Yanga,b, Jinrong Zhua,b   

  1. a School of Chip Industry, Hubei University of Technology, Wuhan 430068
    b Hubei Engineering Technology Research Center of Energy Photoelectric Device and System, Wuhan 430068
  • Received:2021-11-24 Published:2022-04-28
  • Contact: Xinguo Ma
  • Supported by:
    National Natural Science Foundation of China(51472081)

采用平面波超软赝势方法研究了二维单层MoSi2X4 (X=N, P, As)的稳定性、电子结构和光学性质. 研究结果显示, 基于单层MoSi2N4的两种同分异构体M1和M2所构建的六种晶体结构具有较好的动力学稳定性. 通过能带和有效质量的计算, 单层MoSi2N4在MoSi2X4 (X=N, P, As)六种晶体结构中显示出最宽的间接带隙和最高的载流子迁移率. 随后带边电位的计算结果表明, 单层MoSi2N4带边势分别为M1: –0.368、1.416 V, M2: –0.227、1.837 V, 其结果相较于MoSi2P4和MoSi2As4导带边电位更负, 价带边电位更正, 是六种晶体结构中最适合用作光催化剂的材料. 同时, 光吸收谱的计算结果显示, 单层MoSi2N4的光学吸收表现出明显的各向异性, 在可见光和紫外光波段内具有较强的光吸收能力, 说明其在可见光催化领域有着潜在的应用前景. 这些结果为进一步深入研究二维单层MoSi2N4在光催化水解领域的应用提供了理论指导.

关键词: MoSi2N4, 电子结构, 光催化, 第一性原理, 光学性质

Two-dimensional systems have served as potential materials in the generation of clean energy and energy storage, which are attributed to their particular advantages in photovoltaic, photocatalytic and electrochemical fields. Recently, the two-dimensional monolayer MoSi2N4 has been successfully fabricated. Motivated by these recent experimental results, herein the structural stability, electronic structures and optical properties of monolayer MoSi2X4 (X=N, P, As) using the method of plane-wave ultrasoft pseudopotentials were investigated. Six crystal structures were constructed based on the monolayer MoSi2N4 isomers M1 and M2. The phonon spectra did not show negative frequency vibration mode in the entire Brillouin region, indicating good dynamic stability. By analyzing the density of states, it can be known that the top of the valence band and the bottom of the conduction band of the six crystal structures are mainly contributed by MoX2 (X=N, P, As) orbitals. Energy band structures and effective masses show that the monolayer MoSi2N4 exhibits the widest indirect band gap and the highest carrier mobility among the six crystal structures. The band edge potentials show that the monolayer MoSi2N4 band edge potentials are M1: –0.368, 1.416 V and M2: –0.227, 1.837 V, respectively. Compared with MoSi2P4 and MoSi2As4, the monolayer MoSi2N4 has a more negative potential of the conduction band edge and a more positive potential of the valence band edge, indicating that it is the most suitable material for photocatalysts among the six crystal structures. Meanwhile, the optical absorption spectrum shows that the optical absorption of monolayer MoSi2N4 exhibits excellent optical absorption ability in visible and ultraviolet wavelengths, indicating that it has a potential application prospect in the field of visible photocatalysis. The results provide theoretical guidance on the application of monolayer MoSi2N4, for further research in the field of photocatalytic hydrolysis.

Key words: MoSi2N4, electronic structure, photocatalysis, first-principle, optical property