DFT study of structural and electronic properties of MoS2(1-x)Se2x alloy (x=0.25)

First-principles calculations have been performed to study the structural features of the monolayer MoS2(1-x)Se2x (x = 0.25) alloy and its electronic properties. We studied the effects of the relative positions of Se atoms in a real monolayer alloy. It was demonstrated that the distribution of the Se atoms between the top and bottom chalcogen planes was most energetically favorable. For a more probable distribution of Se atoms, a MoS2(1-x)Se2x (x = 0.25) monolayer alloy is a direct semiconductor with a fundamental band gap equal to 2.35 eV (calculated with the GVJ-2e method). We also evaluated the optical band gap of the alloy at 77K (1.86 eV) and at room temperature (1.80 eV), which was in good agreement with the experimentally measured band gap of 1.79 eV. Published by AIP Publishing.