Effects of strain and an external electric field on the electronic and optical properties of mutilayer SnC

Two-dimensional semiconducting materials play a crucial role in advancing nano-optoelectronic devices. This study systematically explores stability, electronic and optical properties of multilayer SnC using first-principles calculations. The phonon analysis reveals that the SnC structures with one to four layers remain stable across a wide range of strains. The band gaps and optical properties can be flexibly modulated by layer number, strain, and an external electric field. The indirect bandgap of multilayer SnC decreases as tensile strain increases but expands with increasing compressive strain. Compressively strained monolayer- and bilayer-SnC undergo an indirect-to-direct bandgap transition. The optical spectra reveal that multilayer SnC exhibits significant sunlight absorption across the visible and ultraviolet regimes. In the ultraviolet range, the absorption intensity enhances as the layer count increases. Additionally, the application of tensile strain and a positive electric field leads to a gradual redshift of the optical spectra, while compressive strain causes a blueshift. These tunable electronic and optical properties suggest that multilayer SnC holds great potential for the design of nano-optoelectronic devices.