Calculation of the excited states of two-dimensional MoSi2N4 layered material semi doped with Cr and W respectively

Abstract. The optical absorption properties of the two-dimensional (2D) MoSi2N4 monolayer is often a focus of research. By semi doping Cr and W at M sites, the influence of M-site atoms on the optical absorption properties of MA2Z4 series materials was investigated. The results show that the atomic layer spacing of 2D materials has some changes after the semi doping of the Cr and W elements, but the entire crystal structure is not significantly different. The semi doping of Cr atoms makes the MoSi2N4 monolayer have an additional absorption peak, the highest absorption peak of the Mo0.5Cr0.5Si2N4 monolayer has a large red shift corresponding to the wavelength, and the width of the absorption peak is also greatly improved. The semi doping of W element results in a red shift of the strongest absorption peak and an increase of the maximum absorption intensity of the Mo0.5W0.5Si2N4 monolayer.