基于第一性原理, 对不同P原子掺杂浓度的二维SiC的几何结构、电子结构和光学性质进行了研究。结果表明：随着P掺杂浓度的增加, P掺杂二维SiC的晶格常数变小, 带隙减小; 价带主要由C-2p, Si-3p和P-3p态电子杂化构成, 导带主要由Si-3p态电子构成。P削弱了C—Si键的共价性, 增加了离子性。P掺杂扩大了二维SiC的光吸收范围, 吸收系数和折射率随掺杂浓度的增加而增大, 表明P掺杂能有效提高二维SiC对可见光和红外光的吸收。

The geometrical structures, electronic structures and optical properties of the two-dimensional (2D) SiC doped with P with different concentrations are investigated by the first principle method. The results show that, the lattice constant and the bandgap of 2D SiC doped with P gradually decrease with the increase of P doping concentration. The valence band is mainly composed of the hybridization of the electrons of C-2p, Si-3p and P-3p states, while the conduction band is mainly composed of the electrons of Si-3p state. The P doping weakens the covalency and increases the ionic property for the C—Si bond. The P doping expands the optical absorption range of 2D SiC, and makes the absorption coefficient and the refractive index increase with the increase of doping concentration, which indicates that P doping can effectively improve the absorption for both the visible and infrared light.