Formation and electron field emission of graphene films grown by hot filament chemical vapor deposition

Graphene films with different structures were catalytically grown on the silicon substrate pre-deposited with a gold film by hot filament chemical vapor deposition under different conditions, where methane, hydrogen and nitrogen were used as the reactive gases. The morphological and compositional properties of graphene films were studied using advanced instruments including field emission scanning electron microscopy, micro-Raman spectroscopy and X-ray photoelectron spectroscopy. The results indicate that the structure and composition of graphene films are changed with the variation of the growth conditions. According to the theory related to thermodynamics, the formation of graphene films was theoretically analyzed and the results indicate that the formation of graphene films is related to the fast incorporation and precipitation of carbon. The electron field emission (EFE) properties of graphene films were studied in a high vacuum system of ∼10−6 Pa and the EFE results show that the turn-on field is in a range of 5.2-5.64 V μm−1 and the maximum current density is about 63 μ A cm−2 at the field of 7.7 V μm−1. These results are important to control the structure of graphene films and have the potential applications of graphene in various nanodevices.