External-strain induced transition from Schottky to ohmic contact in Graphene/InS and Graphene/Janus In2SSe heterostructures

Abstract

The application of 2D materials in FETs inevitably involves contact with metals, which can dramatically affect the performances of electronic devices. Hence, controlling contact performances to form low-resistance Ohmic contact between the metal electrode and semiconductor materials is crucial. Therefore, the vdW stackings of G/InS, G/SIn2Se and G/SeIn2Se heterostructures are designed and investigated by density functional theory, the results indicate that the Schottky barrier height (SBH) of three heterostructures are 0.17 ​eV, 0.31 ​eV and 0.53 ​eV, respectively. Moreover, the SBH can be significantly modulated by external biaxial strain. Meanwhile, the tunneling barriers can be reduced through controlled the interface distance. Considering the Schottky barrier and the tunneling barrier, the G/InS heterostructures has the best performance and controllability. These theoretical studies not only provide fundamental properties of G/InS, G/SIn2Se and G/SeIn2S vdW heterostructures, but also provide new strategy for designing high-performance FETs based on G/InS and G/In2SSe heterostructures.