Realizing semiconductor to metal transition in graphitic ZnO and MoS2 nanocomposite with external electric field

Abstract

First-principles calculations have been used to investigate the structural and electronic properties of graphitic ZnO and MoS₂ (g-ZnO/MoS₂) nanocomposites. It is found that the binding strength of g-ZnO/MoS₂ exhibits strong dependence of atomic arrangement of g-ZnO relative to MoS₂. The coupling interaction of g-ZnO/MoS₂ obviously reduces the semiconducting band gaps, compared to both individual sheets, which are sensitive to its stacking orders. Interestingly, the vertical external electric field (E-field) can be applied to enhance the stability of g-ZnO/MoS₂ and increase charge transfers between these two component. Furthermore, the E-field with the positive direction from MoS₂ to g-ZnO can tune the band gap of g-ZnO/MoS₂ nanocomposites, whereas this nanocomposites produce the semiconducting to metallic behavior transitions when the E-field changes from positive to negative direction, regardless of the stacking pattern. The tunable electronic properties of g-ZnO/MoS₂ nanocomposites under the E-field are attributed to the changes in electrostatic potential difference between atom layer of MoS₂ and interlayer region close to g-ZnO. Present results suggest that the g-ZnO/MoS₂ heterojunction provides promising applications for MoS₂-based optoelectronic and nanoelectronic devices, such as fabricating field effect transistor (FET).