Highly efficient field emission properties of a novel layered VS2/ZnO nanocomposite and flexible VS2 nanosheet

Abstract

Multi-layered VS₂ nanosheets were synthesized via a facile hydrothermal process without using any additives or surfactants. Due to the large quantities of sharp edges, a VS₂ nanosheet can serve as an efficient edge emitter for field emission (FE). The FE properties of VS₂ nanosheets were investigated for the first time. The results indicated that the VS₂ nanosheets had an excellent field emission performance with a turn-on field of ∼1.4 V μm⁻¹ and a threshold field of ∼2.6 V μm⁻¹ on a Si substrate. Moreover, the FE properties of ZnO-coated VS₂ nanosheets were also investigated. The VS₂/ZnO nanocomposite showed enhanced field emission properties with a turn-on field of ∼1.2 V μm⁻¹ and a threshold field of ∼2.2 V μm⁻¹, as well as an excellent emission stability without significant current degradation, which resulted from a well contacted metal–semiconductor junction and extra emission sites. In addition, the FE properties of the VS₂ nanosheets were preserved on a highly flexible polyethylene terephthalate (PET) substrate. Approximately the same values of the turn-on field (∼1.8 V μm⁻¹) and the threshold field (∼3.2 V μm⁻¹) were measured on bent and unbent PET substrates.