A DFT study of the electronic and optical properties of four 2D thin films

Abstract

The optical properties of 2D semiconductors display a wealth of knowledge regarding their physicochemical parameters, including their electronic and phonon states, as well as the existence and kind of defects and imperfections. Furthermore, two-dimensional substances optical characteristics are critical within a few applications, such as optical fiber coatings and lens coverings. In this path, we compute the optical properties, e.g., absorption, conductivity, refractive index, and dielectric function of new orthorhombic SiX and SiX2 (X = As or P) 2D materials, employing density functional theory. Our HSE calculations demonstrate that the SiX and SiX2 monolayers are direct and indirect semiconductors. The imaginary part of the dielectric function, ϵ2(ω) leaves at approximately 16.00 eV, which correlates to the power loss function, according to our GGA simulations. Moreover, when the frequency of the light source is greater than the photon energy, which is ∼ 16.00 eV, our generalized gradient approximation results reveal that our thin films are translucent substances. Additionally, we have discovered that as As evolves P, the conductivity value rises. The primary absorption peaks of the SiX and SiX2 layers along the in-plane polarization are positioned in the ultra-violet spectrum of light, suggesting that they could be a good choice for producing superior photodetectors, according to the optical study.