Tailoring the electronic and optical properties of ZrS2/ZrSe2 vdW heterostructure by strain engineering

Abstract

Under framework of first-principles calculation, we construct ZrS2/ZrSe2 heterostructure and explore the effects of the uniaxial and biaxial strains on its electronic and optical properties. Band structure shows the unstrained ZrS2/ZrSe2 heterostructure has a type-II band alignment. The large binding energy and small interface distance indicate there is a chemical combination between ZrS2 and ZrSe2 layers beyond the van der Waals interaction. Due to the redistribution of charge, a built-in electric field from ZrSe2 to ZrS2 is formed on the interface of the ZrS2/ZrSe2 heterostructure. In addition, constructing the ZrS2/ZrSe2 heterostructure can enhance light absorption intensity. Then we investigate the effects of uniaxial and biaxial strains in the range of −8%∼8% on the electronic and optical properties of the ZrS2/ZrSe2 heterostructure. The band gap of the ZrS2/ZrSe2 heterostructure increases (decreases) with the increase of tensile (compressive) strain, this tunable band gap shows its potential applications in electronic devices. The band type is very sensitive to strain, because the type-II alignment can be converted to type-I alignment. In addition, under uniaxial (−4% and −2%) and biaxial (−2%) compressive strains, a red-shift phenomenon is occurred compared to the unstrained ZrS2/ZrSe2 heterostructure, indicating the better optical gas sensitivity and can be used in infrared light detectors. These findings make possible the application of two-dimensional ZrS2/ZrSe2 heterostructure in multifunctional electronic and optoelectronic devices.