Strain-induced electronic properties of van der Waals heterostructures based on tin dichalcogenides

As a newly emerged form of two-dimensional material, tin dichalcogenides have attracted considerable interest, and building van der Waals (vdW) heterostructures based on them could open up new applications. Here, six vdW heterostructures based on SnS2 and SnSe2 are investigated via first-principle calculations. Except for graphene/SnS2(SnSe2), which behaves as a metal, the other heterostructures including HfS2/SnS2(SnSe2) and ZrS2/SnS2(SnSe2) all behave as a semiconductor. Furthermore, particular attention is paid to the tunable electronic properties of the semiconductor heterolayers under differing in-plane biaxial strain. It is found that both tensile and compressive strain can effectively modulate the band structures and carrier effective mass. The strain changes the band gaps of the semiconductor heterostructures considerably, ultimately causing either a semiconductor-to-metal transition or a variation in the band edge. Analyzing the projected density of states and charge density difference shows that these changes are due mainly to the shifts in energy states and interlayer charge transfer of the vdW heterostructures. The present study suggests that vdW heterostructures based on tin dichalcogenides are viable candidates for nanoscale electronic and optoelectronic applications.