Open AccessExcited State Properties of Layered Two-Dimensional MSi2N4 (M = Mo, Cr, and W) Materials from First-Principles Calculations
Author(s) -
Wangyang Ding,
Zhouhong Xue,
Jiayu Li,
Mingyang Li,
Liang Bai,
Zhou Qi,
Xin Zhou,
Ying Peng,
Miao Liu
Publication year - 2022
Publication title -
ecs journal of solid state science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.488
H-Index - 51
eISSN - 2162-8777
pISSN - 2162-8769
DOI - 10.1149/2162-8777/ac4c80
Subject(s) - excited state , materials science , monolayer , atom (system on chip) , atomic physics , electron , absorption (acoustics) , absorption spectroscopy , ultraviolet , excitation , layer (electronics) , physics , nanotechnology , optics , optoelectronics , quantum mechanics , computer science , composite material , embedded system
Two-dimensional (2D) MoSi 2 N 4 layered material successfully prepared in the experiment was shown to have good light absorption performance, although its internal mechanism is not clear. We discuss the effects of replacing Mo with W and Cr atoms, respectively, on the light absorption performance of a 2D MoSi 2 N 4 monolayer through first-principles calculations. M-site atoms play a major role in the accumulation of electrons in MA 2 Z 4 system materials. In the visible light region, as the excited state is higher, the number of holes that appear on the N atom layer next to the central layer decreases, whereas those appearing on the N atoms of the outermost layer at both ends increase in number, indicating the research value of Z-site atoms in MA 2 Z 4 system. More importantly, the electrons of Si atoms in the sub-outer layer will transfer when the excitation energy is sufficient, and the Mo atoms in the center layer will obtain electrons not only from other atoms but also from themselves. Replacing Mo atoms in the monolayer of MoSi 2 N 4 with Cr atoms can redshift the ultraviolet-visible spectrum (UV) and reduce the height of the strongest absorption peak. Simultaneously, replacing MoSi 2 N 4 monolayer with W atoms causes the blue shift of the ultraviolet-visible spectrum.