Visible-blind UV-Detector properties of monolayer calcium chloride: DFT calculations of its structural, mechanical, electronic and optical properties

Designing new two-dimensional (2D) materials with novel band structures has continuously attracted research interest because of their fundamental science and potential applications. Here we report a unique 2D hexagonal structure of calcium chloride (h-CaCl2) monolayer featuring quasi-planar hexa-coordinate calcium and chloride. In this paper, structural, electronic and optical properties of the h-CaCl2 have been studied. We determine the most stable site for halogens on the h-CaCl2. The calculations are performed on a single layer 3 x 3 x 1 supercell h-CaCl2 within the framework of density functional theory (DFT) to have the maximum computation accuracy. The results show that the h-CaCl2 is a semiconductor with a relatively wide band gap of 5.78 eV. Real and imaginary parts of the dielectric function for an isolated single-layer h-CaCl2 are investigated. Adsorption and reflection calculation results reveal optical blindness of the system within the visible range of the electromagnetic spectrum and prove its suitability for ultraviolet (UV) detection applications.