First-principles predication of facet-dependent electronic and optical properties in InSe/GaAs heterostructure with potential in solar energy utilization

Abstract Building two-dimensional (2D) heterostructure emerges novel properties, attracting great attention in materials science. Here, we design InSe/GaAs heterostructures and explore their novel photoelectric properties using first-principles method. Heterostructures have been shown to be direct bandgap semiconductors with type-II band alignment. Meanwhile, the electronic properties of heterostructures are not only sensitive to stacking model but also strongly dependent on the facet of GaAs contacting InSe. The heterostructures, with As-facet contacting InSe, are confirmed to be preeminent photocatalyst for water splitting. While formed with Ga-facet, heterostructures can be used as appropriate photovoltaic material. All heterostructures possess broad absorption range, with high absorption coefficients (∼105). Besides, the carrier mobilities are outstanding. Therefore, the above prediction results make the InSe/GaAs heterostructures promising to be used in solar energy utilization.