α-In2Se3/Nb-doped MoSh2 heterojunction: a first-principles study

The α-In₂Se₃ material is a two-dimensional ferroelectric semiconductor whose structural asymmetry gives it spontaneous polarization properties, and exhibits a direct bandgap structure when it is multilayered. α-In₂Se₃ is an n-type semiconductor, which is usually used in experiments to form heterojunctions with p-type semiconductors to prepare photodetectors. In this paper, we designed α-In₂Se₃/Nb-doped MoS₂ heterojunction, because Nb doping is a good p-type dopant for MoS₂. Our research shows that: the heterojunction exhibits type-Ⅱ band alignment; the band offset can be changed by the out-of-plane polarization direction; doping can modulate the Fermi energy level position of MoS₂ and thus further modulate the band alignment and band offset. The α-In₂Se₃/Nb-doped MoS₂ heterojunction is expected to be applied to the field of photodetectors, and we proposed a method to adjust the band alignment of the heterojunction by adjusting the doping concentrations.