In this paper, a series of grahene films were fabricated on Ni coated Al2O3 ceramic substrates by using microwave plasma-assisted chemical vapor deposition (MPCVD) technique. Raman spectroscopy and scanning electron microscope (SEM) were used to study the microstructure and surface morphology of the film. The field emission (FE) property of graphene films was measured in a high vacuum system. Field electron emission results showed a turn on field is 3.5 V/μm, and current density is 90μA/cm2 at an electric field of 6 V/μm. The phenomenon of field emission was unstable and the current density was too small (no one exceeds 1mA/cm2). So the preparation method and process of graphene field emission device need further optimization, meanwhile, the mechanism and property of field emission require fully research.
Diamond films were deposited on a silicon substrate by microwave plasma chemical vapor deposition system, and its oxidation experiments were carried out in atmospheric environmental condition by using a muffle furnace. Inatmospheric environment (the temperature is from 400°C to 900°C) the oxidation resistance of diamond thin films was investigated. The results indicate that under the atmospheric environment diamond thin film surface morphology did not change after 6 hours at 400°C. Diamond thin film surface morphology began to change after 2 hours at 600°C, and when time was extended to 4 hours, the diamond thin film surface morphology changed significantly. The surface morphology of diamond films began to change after 15 minutes at a 700°C condition and when time was extended to 6 hours diamond films were all destroyed. All the diamond films on the silicon substrate disappeared completely in 20 minutes at 900°C. The intact crystal face is the reason that natural diamond has stable chemical property. The crystal face of synthetic diamond film has a lot of defects, especially on the side. Oxidation of the diamond films begin with the grain boundary and defects.