Tunable electronic structures of germanane/antimonene van der Waals heterostructures using an external electric field and normal strain**Project supported by the National Natural Science Foundation of China (Grant No. 11864011).

Abstract

Van der Waals (vdW) heterostructures have attracted significant attention because of their widespread applications in nanoscale devices. In the present work, we investigate the electronic structures of germanane/antimonene vdW heterostructure in response to normal strain and an external electric field by using the first-principles calculations based on density functional theory (DFT). The results demonstrate that the germanane/antimonene vdW heterostructure behaves as a metal in a [−1, −0.6] V/Å range, while it is a direct semiconductor in a [−0.5, 0.2] V/Å range, and it is an indirect semiconductor in a [0.3, 1.0] V/Å range. Interestingly, the band alignment of germanane/antimonene vdW heterostructure appears as type-II feature both in a [−0.5, 0.1] range and in a [0.3, 1] V/Å range, while it shows the type-I character at 0.2 V/Å. In addition, we find that the germanane/antimonene vdW heterostructure is an indirect semiconductor both in an in-plane biaxial strain range of [−5%, −3%] and in an in-plane biaxial strain range of [3%, 5%], while it exhibits a direct semiconductor character in an in-plane biaxial strain range of [−2%, 2%]. Furthermore, the band alignment of the germanane/antimonene vdW heterostructure changes from type-II to type-I at an in-plane biaxial strain of –3%. The adjustable electronic structure of this germanane/antimonene vdW heterostructure will pave the way for developing the nanoscale devices.