High Average Emission Sites Density of Electron Field Emission from Broad Area Diamond-Amorphous Carbon Thin Films

Diamond-amorphous carbon films were deposited on metal Mo substrates by using microwave chemical vapor deposition technique and masked technique(the Mo substrates were pretreated by special techniques).Round area of diamond-amorphous carbon films is 0.78±0.001cm^(2).The films were characterized by x-ray diffraction,Raman spectrum,optical microscopy,and scanning electron microscopy.The result of experiment indicates that diamond-amorphous carbon films with graphite particulates surface morphologies and diamond submicro-sized crystalline grains located in it were obtained.Based on this,a novel electron field emission device was made.The lowest turn-on field of 1V/μm,high average emission current density of 8.0±0.1mA/cm^(2),and high average emission sites density of(2.00±0.03)x 10^(3) sites/cm^(2) from a broad well-proportioned emission area of 0.780±0.001 cm^(2) were obtained,and the smaller the graphite particulate,the better the emission character.Field enhancement due to a‘projection on a projection’geometry could be a partial explanation of the result.