Field emission properties of hybrid few-layer graphene-carbon nanotubes

Few-layer graphene (FLG) and carbon nanotube (CNT) hybrid is prepared by in situ growth of FLG on the walls of CNTs, using PECVD, without catalyst. The amount and size of FLG can be controlled by total gas pressure and growth time. The field emission (FE) characteristics of CNTs coated with different-density FLG were studied, and an FE phenomenon schematic and electrostatic field equipotential model of these FLG-CNTs were proposed. These results show that the geometrical morphology of FLG plays an important role in the FE property of hybrid FLG-CNTs. The medium-density FLG on the CNTs exhibits excellent FE properties, with a low turn-on electric field and threshold field, as well as large field enhancement factor, which are much better than those of the as-grown CNTs. The excellent FE properties of the FLG-CNT hybrids make them promising candidates for high-performance FE emitters.