Tunable Schottky contact in the graphene/WSe2(1−x)O2x heterostructure by asymmetric O doping

Tuning the electrical transport properties of a nanoelectronic device with a p-type Schottky contact remains a grand challenge. To solve this issue, we explore the effectiveness of asymmetric O doping on performance improvements of the graphene/WSe2(1−x)O2x (Gr/WSe2(1−x)O2x) heterostructure using first-principles calculations. The results show that graphene and the WSe2(1−x)O2x monolayer could form a stable van der Walls interface. Further, the controlled asymmetric O doping at different positions and concentrations regulates the electronic properties of the Gr/WSe2(1−x)O2x heterostructure in terms of the type and the height of the Schottky barrier. It is found that a transformation of a Schottky contact from an n-type to p-type is realized by changing the position of the O dopant from inside to outside, and a high Schottky barrier height of 0.72 eV in the undoped Gr/WSe2 heterostructure can be reduced to 0.06 and 0.09 eV for the O doing inside and outside the interface, respectively. In addition, when the O doping concentration increases to 67% both inside and outside of the interface, the Ohmic contacts are observed. Last, the controllable Schottky contact in the Gr/WSe2(1−x)O2x heterostructure is induced by the charge redistribution of the interface, which is caused by the shift of the Fermi level. This work may provide a promising method to improve the electronic performance of the Gr/WSe2 nano field effect transistors.