Doping-driven physical properties and electronic transition in 2D transition metal dichalcogenides Mo1-XAXS2 (A= [Nb, V], X = 0.25, 0.50, 0.75, 1.00): A First principle study

First principle density functional theory was employed to investigate the physical properties and electronic transition of doped two-dimensional molybdenum disulphide (MoS₂) with transition metal niobium (Nb) and vanadium (V) at varying doping concentration. The objective was to study how controlled doping affects the physical characteristics of doped MoS₂for potential photodetection application. The obtained result reveal that Nb doping leads to progressive lattice expansion and rapid transition from semiconducting to metallic behavior which is attributed larger atomic radius and fewer valence electrons as compared to Mo. While V doping results in slight contraction of the lattice and a more gradual narrowing of the energy gap and retained it semiconducting nature at low and moderate doping concentration. The elastic properties result shows that Nb doping softens the material significantly than V doped which is due to weakened M − S bonding. The Band structure and total density of states analysis confirm the introduction of impurity levels and p-type character in Nb-doped systems, whereas V-doped systems show hybridization near the Fermi level with localized to semi-metallic transitions. These findings demonstrate that V doping offers a more stable and tunable route for enhancing the optoelectronic performance of MoS₂, making it promising candidate for broadband photodetector.