Electronic Structure and Optical Properties of Bisi/Bisei Heterojunctions

Abstract

In this paper, the optoelectronic properties of Janus BiSI and BiSeI monolayers and their BiSI/BiSeI heterojunction structured materials are calculated based on the First-Principles computational method of density-functional theory (DFT). The BiSI/BiSeI heterojunction structure models of 18 highly symmetric stacking structures are constructed, and three stable heterojunction structures are obtained by computational analysis and binding energy. According to the different stacking methods, the three heterojunction structures have different impacts on the optical properties, the peak value of heterojunction absorption becomes larger, the absorption band and the peak wavelength of absorption are red-shifted, and the peak wavelength of absorption is located in the ultraviolet region compared to the monolayer, and the absorbance in the visible region is enhanced by up to 1.44 times compared to the monolayer. The results of this paper show that through the design of heterojunction structure, the electronic structure and energy band band gap of the material can be changed to improve the optoelectronic properties of the material, which provides ideas for the design and application of optoelectronic devices with different needs.

Keywords: Janus monolayer, Janus heterojunction, electronic structure, optical properties, first-principles