In this work, the structural, electrical, and optical properties of bilayer SiX (X= N, P, As, and Sb) are studied using density functional theory. Five different stacking orders are considered for every compound and their structural properties are presented. The band structure of these materials demonstrates that they are indirect semiconductors. The out-of-plane strain has been applied to tune the bandgap and its electrical properties. The bandgap increases with tensile strain, whereas, compressive strain leads to semiconductor-to-metal transition. The sensitivity of the bandgap to the pressure is investigated and bilayer SiSb demonstrates the highest bandgap sensitivity to the pressure. These structures exhibit Mexican hat-like valence band dispersion that can be approved by a singularity in the density of states (DOS). The Mexican-hat coefficient can be tuned by out-of-plane strain. Optical absorption of these compounds shows that the second and lower valence bands due to the high DOS display a higher contribution to optical transitions.

在这项工作中，使用密度泛函理论研究了双层 SiX（X = N、P、As 和 Sb）的结构、电学和光学性质。每种化合物都考虑了五种不同的堆叠顺序，并展示了它们的结构特性。这些材料的能带结构表明它们是间接半导体。已应用面外应变来调整带隙及其电气特性。带隙随着拉伸应变而增加，而压缩应变导致半导体到金属的转变。研究了带隙对压力的敏感性，双层 SiSb 显示出对压力的最高带隙敏感性。这些结构表现出墨西哥帽状价带色散，可以通过状态密度 (DOS) 中的奇点来批准。墨西哥帽系数可以通过面外应变进行调整。这些化合物的光吸收表明，由于高 DOS 导致的第二价带和较低价带对光跃迁的贡献更大。