DFT Analysis of Strain Effect in Bilayer 2D-SiC on Electrical, Optical, Phonon, and Thermodynamic Properties

The recent interest of researchers in two-dimensional silicon carbide ($2 \mathrm{D}-\mathrm{SiC}$) stems from its comparatively wide bandgap and high exciton binding energy. The object of this paper is to evaluate the impact of strain on the phonon, thermodynamics, optical, and electrical properties of bilayer 2D-SiC using first-principles density functional theory. The electrical bandgap of the bilayer 2D-SiC is about 1.45 eV in its indirect form. Exerting tensile strain induces a transformation of the indirect bandgap into a direct bandgap. Under the influence of tensile stresses, the bandgap demonstrates a declining pattern, whereas under compressive strains, it displays an increasing inclination. Moreover, the optical properties of bilayer SiC, including the absorption coefficient, dielectric spectra, and electron energy loss spectra, demonstrate its exceptional ability to efficiently absorb light in both the infrared (IR) and visible ranges. At compressive stresses beyond $-2 \%$, the dynamic stability of a bilayer of SiC diminishes, yet it maintains dynamic stability up to tensile strains up to $+6 \%$. Thus, applied biaxial strain on bilayer SiC can enhance the suitability of this material for sophisticated nanoelectronics and optoelectronic devices.