  Comparing with the conventional semiconductors, the choice of the two
dimensional semiconductor (2DSC) materials is very limited. Based on proper
electron counting, we propose a large family of 2DSCs, all adopting the same
structure and consisting of only main group elements. Using advanced density
functional calculations, we demonstrate the attainability of these materials,
and show that they cover a large range of lattice constants, band gaps and band
edge states, therefore are good candidate materials for heterojunctions. This
family of two dimensional materials may pave a way toward fabrication of 2DSC
devices at the same thriving level as 3D semiconductors.
