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

In recent years, the two-dimensional (2D) semiconductor α-InSe 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-InSe/Au contacts with different polarization directions are studied, and a two-dimensional α-InSe asymmetric metal contact design is proposed. When α-InSe is polarized upward, it forms an n-type Schottky contact with Au. While when α-InSe is polarized downward, it forms a p-type Schottky contact with Au. More importantly, significant rectification effect is found in the asymmetric Au/α-InSe/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-InSe-based transistors.