Substitutional doping at S site of MoS2/G heterostructure: The influence on voltage-current and electronic characteristics

The effect of substitutional doping at S site on the electronic properties of MoS2/Graphene (MoS2/ G) was studied by First-principles calculations. Through the analysis on the energy band and density of states of MoS2/Graphene, it was found that the S vacancy in MoS2 monolayer caused the Dirac point shifted, and produced the defect energy levels at the Dirac point, which hindered the carrier transmission. Periods II-IV elements were doped at the S vacancy to improve the electronic properties and performance of MoS2/G. The calculated results show that the charge transfer of MoS2/G was greatly enhanced by the doping of N, P and As atoms. The current-voltage characteristic of N, P and As-doped G/MoS2/MoS2/G structure has higher drive-current and stable OFF-state current which can reduce device current consumption. For O-doped and Se-doped MoS2/G heterostructures, there is no impurity level introduced, and the Schottky barrier height increase (decrease) with the increase (decrease) of the biaxial strain, meantime the p-type Schottky contact, n-type Schottky contact and Ohmic contact characteristic can be converted mutually by adjusting biaxial strain or vertical external force. Our findings will be of great guiding significance for the designing of interface devices and explorations on nano-electronics.

Automated summary

The substitutional doping of N, P, and As atoms at S sites greatly enhances charge transfer and device performance in MoS2/graphene structures. Additionally, the manipulation of biaxial strain and external forces can convert different contact characteristics in MoS2/graphene heterostructures.