NUCLEATION OF DIAMOND ON GRAPHITIC CARBON

Nucleation of diamond on mainly sp2-bonded (graphitic) carbon has crea ted new concepts on the synthesis of diamond films. In this work, diam ond nucleation from turbostratic carbon (TC) films is presented. The n umber density of diamond crystallites was found to be higher on TC-coa ted 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 polis hing. Diamond did not grow on the. 0002 surface of the highly oriented pyrolytic graphite (HOPG). Although it formed with a very low nucleat ion density, it was possible to nucleate diamond on the edges of the b asal planes of HOPG. To elucidate these results, models which explain the transformation of the graphitic structure to the diamond-cubic str ucture in the graphite stable region are discussed.