EFFECT OF CO2 ADDITION ON DIAMOND GROWTH BY DC ARC PLASMA-JET CHEMICAL-VAPOR-DEPOSITION

The effect of adding carbon dioxide (CO2) to the reactant gases was st udied in a dc arc plasma jet chemical vapour deposition (CVD) for the synthesis of diamond films. The fabricated films were characterized by Raman scattering spectroscopy and scanning electron microscopy. Witho ut CO2, Raman spectra of these films display only graphitic peaks. As CO2 is added, faceted diamond crystal is observed in micrographs from scanning electron microscopy and a sharp diamond peak in the Raman spe ctrum appears. At a CO2/CH4 ratio of 2.0, diamond films exhibit a pure diamond Raman peak at 1333 cm(-1) with small nondiamond carbon peaks. In addition, plasma diagnosis was performed using optical emission sp ectroscopy.