NUCLEATION OF DIAMOND ON GRAPHITIC CARBON

Nucleation of diamond on mainly sp2-bonded (graphitic) carbon has created new concepts on the synthesis of diamond films. In this work, diamond nucleation from turbostratic carbon (TC) films is presented. The number density of diamond crystallites was found to be higher on TC-coated substrates than uncoated substrates. The diamond crystallites were characterized using transmission electron microscopy and diffraction and it was found that they were highly twinned. Diamond was also grown on polycrystalline graphite substrates with and without diamond polishing. Diamond did not grow on the. 0002 surface of the highly oriented pyrolytic graphite (HOPG). Although it formed with a very low nucleation density, it was possible to nucleate diamond on the edges of the basal planes of HOPG. To elucidate these results, models which explain the transformation of the graphitic structure to the diamond-cubic structure in the graphite stable region are discussed.