Interfacial electronic states and self-formed asymmetric Schottky contacts in polar α-In₂Se₃/Au contacts

In recent years, the two-dimensional (2D) semiconductor α-In₂Se₃ has great potential for applications in the fields of electronics and optoelectronics due to its spontaneous iron electrolysis properties. Through ab initio electronic structure calculations and quantum transport simulations, the interface properties and transport properties of α-In₂Se₃/Au contacts with different polarization directions are studied, and a two-dimensional α-In₂Se₃ asymmetric metal contact design is proposed. When α-In₂Se₃ is polarized upward, it forms an n-type Schottky contact with Au. While when α-In₂Se₃ is polarized downward, it forms a p-type Schottky contact with Au. More importantly, significant rectification effect is found in the asymmetric Au/α-In₂Se₃/Au field-effect transistor. The carrier transports under positive and negative bias voltages are found to be dominated by thermionic excitation and tunneling, respectively. These findings provide guidance for the further design of 2D α-In₂Se₃-based transistors.