The electronic properties of C2N/antimonene heterostructure regulated by the horizontal and vertical strain, external electric field and interlayer twist

Abstract

The electronic properties of C2N/antimonene (Sb) van der Waals (vdW) heterostructure are investigated based on the density functional theory. The results show that the C2N/Sb vdW heterostructure behaves type-II band alignment with a direct Eg of 0.35 eV. The electronic structure can be adjusted by horizontal (vertical) strain, electric field, interlayer twist, and vertical strained-twisted cases, respectively. The horizontal strain shows a more extensive controlling range of Eg than the vertical strain, but the vertical strain adjusting shows better linear features than the horizontal strain. When applying an electric field, the maximum Eg can reach 1.4 eV with Type-I band alignment, which has potential in transistors, solar cells, Light Emitting Diode(LED), and other applications. The heterostructure keeps robust type-II band alignment with different twist angles between C2N and Sb monolayer, which contributes to efficient separation of photo-generated electron-hole pairs as photovoltaic and optical detector devices. When the vertical strain is applied on the twisted heterostructure, the band alignment, Eg, and energy states near the Fermi energy (EF) change obviously due to orbital hybridization strengthened. Our results suggest that there are various means to regulate the electronic properties of heterostructures.