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±0.001cm². 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/cm², and high average emission sites density of (2.00±0.03) x 10³ sites/cm² from a broad well-proportioned emission area of 0.780±0.001 cm² 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.