Robust broken-gap MoTe2/ZrS2 van der Waals heterostructure

Two-dimensional van der Waals (vdW) heterostructures with several possibilities of band edge alignment are promising candidates in the design of semiconductor junction devices with good electrostatic control. We predict a robust broken-gap band alignment for the MoTe2/ZrS2 vdW heterostructure and uncover the underlying mechanism. Our first-principles calculations reveal that upon formation of the vdW heterostructure a small amount of charge is transferred between the layers which sits on the central transition metal atoms and is responsible for the band edge alignment. Moreover, the lattice-mismatch-induced in-plane strain and the interfacial polarization are shown to play no role in band alignment. However, we find a weak sensitivity of the electronic structure and band edge alignment of the vdW heterostructures to an external normal-to-plane strain or electric field. Our findings are helpful in designing heterojunction devices with desired electronic structures.