Structure and electronic properties of MoS1.5Se0.5 alloy from first-principals calculations

Abstract

The effects of relative positions of Se atoms in a real monolayer alloy MoS1.5Se0.5 have been studied. It is demonstrated that the distribution of Se atoms between top and bottom chalcogen planes is most energetically favorable. For a more probable distribution of Se atoms MoS1.5Se0.5 monolayer alloy is a direct semiconductor with the fundamental band gap equal 2.35 eV. We have also evaluated the optical band gap of alloy at 77 K (1.86 eV) and room temperature (1.80 eV), which is in good agreement with the experimentally measured band gap of 1.79 eV