Strain-regulated electronic and optical properties of InSe/WS2 heterostructure from first-principle calculations

Abstract

InSe/WS2 heterostructure (HS) was constructed in this study to combine the excellent properties of these two monolayer semiconductors. The calculation of enthalpy of formation, phonon spectrum, and elastic constants of heterostructure based on first-principle proves that InSe/WS2 HS has good stability and mechanical property. The study of electronic properties illustrates that InSe/WS2 HS is a type II direct band gap semiconductor with photogenerated electrons (holes) located mainly on the InSe (WS2)-layer, the electron mobility of heterostructure increased a lot (4357.65 cm2V−1s−1), and the hole mobility enhanced a little after the combination of the heterostructure. In addition, the band gap is greatly reduced, providing it with a stronger light absorption capability. Likewise, optical properties (absorption coefficient, reflectivity, loss function, refractive index, dielectric function, and photoconductivity) can be modulated under applied biaxial strain. More importantly, the band gap can be significantly tuned under applied strain (direct ⇆ indirect, 0.02 eV ∼ 1.5eV) to meet the different requirements of devices for semiconductor devices.