Résumé:
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.
