Tunable electronic properties of an Sb/InSe van der Waals heterostructure by electric field effects

The electronic properties of an Sb/InSe heterostructure are investigated by using the density functional theory method. A type-II staggered-gap band alignment is achieved from the Sb/InSe vdW heterostructure with the Sb layer dominates the lowest energy holes as well as the lowest energy electrons are contributed by the InSe layer, which facilitates the spatial effective separation of photogenerated electron–hole pairs. Additionally, an indirect–direct band gap transition can be triggered via varying the interlayer distance. More fascinatingly, the characteristic of type-II band alignment is robust, while the band gap values are tunable with respect to a moderate external electric field, even leading to an intriguing semiconductor–metal transition at a strong electric field. These results are expected to provide meaningful guidelines for the design of novel nanoelectronic and optoelectronic devices based on the Sb/InSe heterostructure.