Effect of surface roughness on field emission from chemical vapor deposited polycrystalline diamond

The effect of surface roughness on electron emission from hydrogenated polycrystalline diamond films is reported. Field emission measurements were performed with both millimeter and nanometer spatial resolution using scanning probe techniques. Surface asperities were removed by ion beam treatment, which resulted in a reduction of the rms roughness from 198 to 94 nm, leading to an increase in the threshold field required for electron emission by about a factor of 2. These results suggest that surface asperities, rather than grain boundaries, are the dominant influence on electron emission in polycrystalline diamond films. (C) 2001 American Institute of Physics.