Phosphorene analogues: isoelectronic two-dimensional group-IV monochalcogenides with orthorhombic structure

Understand

The group-IV monochalcogenides SnS, GeS, SnSe and GeSe form a family within the wider group of semiconductor `phosphorene analogues'.

• Here, we used first principles calculations to investigate systematically their structural, electronic and optical properties, analysing the changes associated with the reduction of dimensionality, from bulk to monolayer or bilayer form.
• We show that all those binary phosphorene analogues are semiconducting, with bandgap energies covering part of the infra-red and visible range, and in most cases higher than phosphorene.
• Further, we found that they have multiple valleys in the valence and conduction band, with spin-orbit splitting of the order of 19-86 meV.