Effect of Au buffer on the field emission characteristics of chemical vapor deposited diamond films

Au-precoating on silicon substrate was observed to enhance the field emission characteristics of diamond films deposited by chemical vapor deposition technique. The emission current density increased substantially from 1 to 100 μA/cm2, while the turn on voltage decreased only moderately from 14 to 10 MV/m due to the application of Au-precoatings. Raman spectra and electron diffraction in transmission electron microscopy (TEM) revealed that both diamond films deposited on Si or Au-coated Si (AuSi) were nanosized crystals. The Au species were assumed to diffuse along grain boundaries, resulting in low resistance diamond films. Abundant supply of electrons via conducting grain boundaries was presumably the mechanism that enhanced the field emission of the diamond films grown on AuSi substrates.