First-principles study on electronic states of In₂Se₃/Au heterostructure controlled by strain engineering

The development of low-dimensional multifunctional devices has become increasingly important as the size of field-effect transistors decreases. In recent years, the two-dimensional (2D) semiconductor In₂Se₃ has emerged as a promising candidate for applications in the fields of electronics and optoelectronics owing to its remarkable spontaneous polarization properties. Through first-principles calculations, the effects of the polarization direction and biaxial tensile strain on the electronic and contact properties of In₂Se₃/Au heterostructures are investigated. The contact type of In₂Se₃/Au heterostructures depends on the polarization direction of In₂Se₃. The more charge transfers from the metal to the space charge region, the biaxial tensile strain increases. Moreover, the upward polarized In₂Se₃ in contact with Au maintains a constant n-type Schottky contact as the biaxial tensile strain increases, with a barrier height Φ _SB,n of only 0.086 eV at 6% strain, which is close to ohmic contact. On the other hand, the downward polarized In₂Se₃ in contact with Au can be transformed from p-type to n-type by applying a biaxial tensile strain. Our calculation results can provide a reference for the design and fabrication of In₂Se₃-based field effect transistors.