Indium Selenide/Antimonene Heterostructure for Multifunctional Optoelectronics

Van der Waals (vdW) heterostructures identify the advantage of integrating excellent properties of the stacked two-dimensional (2-D) materials by vdW interactions, thereby have gained increasing attention in optoelectronic applications recently. However, heterostructures with type-II band aligning and direct bandgap are still scarce for optoelectronics. Herein, within the framework of density functional theory (DFT) calculations, we predict the indium selenide/antimonene heterostructure as a promising candidate for optoelectronic applications. The most energetically stable configuration of indium selenide/antimonene heterostructure presents a direct bandgap of 0.97 eV at HSE06 level. Remarkably, indium selenide/antimonene heterostructure exhibits a type-II band alignment, indicating its favorable capability of electron-hole separation. Carrier mobility computations show that indium selenide/antimonene heterostructure possesses both high electron mobility and hole mobility of up to 10³ cm² V^-1 s^-1, which are superior to that of any individual monolayer InSe and antimonene. The light absorption and photocurrent calculations reveal that InSe/antimonene heterostructure is sensitive to visible and ultraviolet light. The power conversion efficiency of an indium selenide/antimonene thin-film solar cell is up to 17.2%. The multifunctionality endows the indium selenide/antimonene heterostructure a potential candidate for photovoltaic devices and photodetectors.