Tuning electronic and optical properties of two-dimensional vertical van der Waals blue Phosphorene/SnS2 heterostructure by strain and electric field

Abstract

In order to create optoelectronic devices, it is essential to have access to semiconductors with a suitable bandgap, especially those with excellent optical properties that can be electronically tuned. In this paper, we constructed vertically stacked BlueP/SnS2 heterostructures and systematically investigated their crystal structures and optoelectronic properties by first-principles computational methods. Our research shows that BlueP/SnS2 is stacked vertically to create a type-II heterostructure with an indirect band gap of 0.802 eV, separating photogenerated electron-hole pairs effectively. Modifying the band gap of the heterostructure can be effectively achieved by applying biaxial strain and an electric field. The electric field affects the band gap linearly in the −0.5 to 0.5 V/Å range. Furthermore, the band gap reduces under tensile strain or compressive strain. Applying a biaxial strain of −10 % to the heterostructure changes the band alignment from type II to type I. At the same time, the applied electric field does not cause such a transition. Compared to BlueP and SnS2 monolayers, BlueP/SnS2 heterostructures exhibit redshift and blueshift in their absorption spectra. Redshift results from tensile strain or a weak electric field, while blueshift results from compressive strain or a strong electric field. The utilization of BlueP/SnS2 heterostructures in nano- and optoelectronic devices shows excellent potential.