Ab Initio Study of Tunable Electronic Properties of Monolayer Mo1-xWxS2 Alloys

When ternary compounds are created by alloying two lattice-matched nanostructures of different band gaps, such as MoS
2
and WS
2
, the resulting compounds exhibit intriguing variations in optoelectronic properties. Here, we conducted first-principles calculations based on density-functional theory (DFT) to determine the electronic band structures and tunable physical properties of 2D randomly alloyed monolayer Mo
1-x
W
x
S
2
. The variation in the geometrical shape, band structure, contribution from atomic orbitals, Bader charge analysis, the density of states, energetic stability and HOMO-LUMO charge densities for different alloy compositions were assessed. Our investigation reveals that Vegard’s law for band gap deviated as W(x) composition increased, and band gap bowing parameters were determined. Moreover, electronic device parameters such as mobility, effective mass and charge accumulation were calculated, and they can be gradually tuned by varying the composition. The findings of this work revealed the tunability of the physical properties of Mo
1-x
W
x
S
2
by alloying and will be beneficial to design nanoscale electronic and optoelectronic devices with enhanced performance.