Doping effects on electronic structures and current-voltage characteristics of GR/InSe/GR selectors

Abstract

The graphene(GR)/InSe/GR selector was designed based on the rectifying effect of the Schottky barrier at the GR/InSe heterostructure interface. The selector performance was improved by doping groups I–VII A elements, and the effects were studied by first-principles calculations. The band structure results showed that InSe retained p-type semiconductor characteristics only when Se atoms were substitutionally doped by groups IV A (C, Si, Ge) and VI A (O, S) elements. The band gap of the GR/InSe heterostructure doped with group IV A (C, Si, Ge) elements became narrower, and the conductivity became stronger. The band structures of the GR/InSe heterostructures doped with group VI A (O, S) elements were hardly changed. From the plane average electrostatic potential and the charge density difference, it is observed that doping of group IV A (C, Si, Ge) elements reduced the height and width of the Schottky barrier at the interface and enhanced the built-in electric field strength of the heterostructures. Finally, the current-voltage (I-V) curves show that compared with the undoped GR/InSe/GR selector, the on-state current (Ion) and nonlinearity (NL) coefficient of selectors doped with group IVA (C, Si, Ge) elements increased, and the threshold voltage (Vth) and off-state current (Ioff) decreased. It can better suppress the influence of the leakage current on the RRAM, which is important for the development of high-performance and low-power selectors.