Optical and dielectric response of two dimensional WX 2 (X=Cl, O, S, Se, Te) monolayers: a comprehensive study based on density functional theory.

Here, we study the dielectric and optical properties of two-dimensional (2D) WX 2 monolayers, where X is Cl, O, S, Se, and Te. First principle electronic band structure calculations reveal that all materials are direct band gap semiconductors except WO 2 and WCl 2 , which are found to be indirect band gap semiconducting 2D materials. The dielectric response of these materials is also systematically investigated. The obtained results suggest that these materials are suitable as dielectric materials to suppress unwanted signal noise. The optical properties of these 2D materials, such as absorption, reflection and extinction coefficients, refractive index, and optical conductivity, are also calculated from the dielectric function. It is found that these materials exhibit excellent optical response. The present electronic, dielectric, and optical findings indicate that WX 2 monolayers have an opportunity in electronic, optical, and optoelectronic device applications.