Effect of CO₂ Addition on Diamond Growth by DC Arc Plasma Jet Chemical Vapour Deposition

Abstract

The effect of adding carbon dioxide ( CO 2 ) to the reactant gases was studied 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. Without CO 2 , Raman spectra of these films display only graphitic peaks. As CO 2 is added, faceted diamond crystal is observed in micrographs from scanning electron microscopy and a sharp diamond peak in the Raman spectrum appears. At a CO 2 / CH 4 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 spectroscopy.