Efficient band structure engineering and visible-light response in SnS2/GaS heterostructure by electric field and biaxial strain

Abstract

Abstract By means of first-principle methods, the electronic structures and optical properties of 2D SnS2/GaS van der Waals heterostructure (vdWH) were studied. It was found that the band gap values could be modulated by vertical electrical. Besides, the biaxial strain not only tuned the band gap, but also changed the band alignment from type-II to type-I, realizing multi-functional device applications. The positive E-field increase the optical adsorption coefficients in visible region, while the negative E-field decrease the optical adsorption coefficients in visible region and increase the optical adsorption coefficients in ultra-violet region. The tensile strains increase the optical adsorption coefficients in infrared, visible and ultraviolet regions, while the compressive strain decrease the optical adsorption coefficients in visible and ultraviolet region. The results show that the tensile strain and E-field both can modulate the band gap to enhance performance in the visible optical application for SnS2/GaS vdWH materials, but the tensile strain is more efficient.