Effect of strain and electric field on electronic structure and optical properties of Ga₂SeTe/In₂Se₃ heterojunction

Abstract

Stacking two-dimensional materials into heterogeneous structures is an effective strategy to regulate their physical properties and enrich their applications in modern nanoelectronics. The electronic structure and optical properties of a new two-dimensional Janus Ga<sub>2</sub>SeTe/In<sub>2</sub>Se<sub>3</sub> heterojunction with four stacked configurations are investigated by first principles calculations. The heterojunction of the four configurations is an indirect band-gap semiconductor with a type II band structure, and the photoelectron donor and acceptor materials are determined by the polarization direction of two-dimensional In<sub>2</sub>Se<sub>3</sub>. The light absorption is up to 25% in the visible region, which is conducive to the effective utilization of the solar visible light. The biaxial strain can induce direct-indirect bandgap transition, and the applied electric field can effectively regulate the bandgap of heterogeneous structures. The bandgap of AA2 configuration increases monotonically from 0.195 eV to 0.714 eV, and that of AB2 configuration decreases monotonically from 0.859 eV to 0.058 eV. The bands of the heterojunction always maintain the type II structure under the two kinds of configurations. The heterojunctions under compressive strain show better light absorption capacity in the visible region with shorter wavelength. These results reveal the regulatory mechanism of the Janus Ga<sub>2</sub>SeTe/In<sub>2</sub>Se<sub>3</sub> van der Waals heterojunction electronic structure and provide theoretical guidance for the design of novel optoelectronic devices.