Modulating the optical and electrical properties of MoSe2 (Molybdenum diselenide) and WS2 (Tungsten disulfide) monolayer by the adsorption of halogen (F, Cl, Br, I and At) atoms

摘要

Abstract First principle calculations based on a density functional approach are used to study electrical and optical characteristics of MoSe2 (Molybdenum diselenide) and WS2 (Tungsten disulfide) nanostructures adsorbed with halogens such as F, Cl, Br, I and At. Spectral analysis of pristine MoSe2 and WS2 shows substantial absorption peaks in the visible spectrum (380–490 nm) as well as in the complete ultraviolet region (below 400 nm). For nanostructures of MoSe2—F, MoSe2—Cl, MoSe2—Br, MoSe2—I, WS2—Cl, WS2—Br, WS2—I and WS2 –At, absorption peaks are scattered over the entire visible region. It is observed that absorption spectrum peaks shift to higher energy ranges, contributing to blue-shift phenomenon. Structures formed by adsorption of Astatine (At) atom on MoSe2 and Fluorine (F) atom on WS2 leads to red-shift phenomenon where the absorption peaks shift towards the lower energy spectrum range. It is worth noting that all halogen adsorbed structures have excellent performance throughout the entire visible spectrum, making them extremely useful for optoelectronics applications. Furthermore, all measured dielectric constants have been found to coincide with the measured refractive index values.