Tunable electronic and optical properties of InSe/InTe van der Waals heterostructures toward optoelectronic applications

Abstract

Forming novel van der Waals (vdW) heterostructures by combining different two-dimensional (2D) materials is significant to achieve more desirable properties. Using first-principles calculations, we demonstrate the electronic and optical properties of the InSe/InTe van der Waals heterostructure. Our results suggest that this heterostructure has an intrinsic type-II band alignment with a direct band gap. The electrons and holes are respectively localized in the InSe and InTe layers. The spatial separation of the lowest energy electron–hole pairs can occur, implying that the InSe/InTe heterostructure is a good candidate for a high-efficiency solar cell. In addition, the optical absorption in heterostructures can be enhanced compared with both of the monolayers. Moreover, tuning of the values with a direct band gap can be induced by applying normal strain, and the band gap exhibits linear variation. Meanwhile, an intrinsic type-II band alignment can be tuned to become type-I, which is suitable for light emission applications. These results indicate that the flexible InSe/InTe vdW heterostructure can provide new ways to utilize two-dimensional materials in future optoelectronic devices.