First principles study of WSe₂ and the effect of V doping on the optical and electronic properties

Tungsten diselenide WSe2 is a material with an intriguing character that has captivated the attention of researchers; in this study, an ab initio analysis is presented that focuses on the optical and electronic properties of WSe2. The study made use of density functional theory (DFT) by employing the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) density functional and PseudoDojo pseudopotential. The study looked at the properties of both bulk and monolayer WSe2 to determine how the number of layers affects the properties of the material. To further investigate the properties of WSe2, four different systems based on vanadium doped-WSe2 were analyzed from the optical and electronic points of view. The systems contained different percentages of V: (i) WSe2:V 1.4%, (ii) WSe2:V 2.8%, (iii) WSe2:V 5.6%, and (iv) WSe2:V 11.2%. The introduction of vanadium brought about a reduction of the bandgap and a global shift of the projected density of states. The valence band maximum (VBM) also crossed the Fermi level, which is consistent with the p-type nature of vanadium doping. Furthermore, the absorption spectra changed in terms of the position and the intensity of the optical transition as a result of vanadium introduction.