Study of Physical Properties of Transition MetalsDieselenides of the SixthColomn

Abstract

We use first-principles calculations based on Density Functional Theory (DFT) to analyze the structural, electronic, and optical properties of a MoSe2 monolayer, one of the prominent two-dimensional transition metal dichalcogenides (TMDCs) belonging to group VI of the periodic table. Our research focuses on both the pristine material and its behavior under various types of defects, such as a molybdenum vacancy, arsenic substitution at a Mo site, and arsenic interstitial doping. To our knowledge, this work represents the first theoretical study of the latter two defects. The Quantum ESPRESSO package was used to perform the computations, employing the plane-wave pseudopotential approach. To better understand the impact of these defects, we investigated structural optimization, formation energy, band structure, density of states, difference charge density, and a range of optical properties including dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, optical conductivity, and energy loss function. The study found that defect engineering significantly alters the electronic properties of MoSe2, such as the band gap and the electronic states near the Fermi level. It also introduces localized states and causes shifts in various optical spectra, suggesting potential applications in optoelectronic devices.Moreover, our results are in good agreement with previously reported theoretical and experimental studies, which further validates the reliability of our findings. This study sheds light on the tunability of 2D TMDC materials through controlled defect introduction.