Diamond synthesis by microwave plasma chemical vapor deposition using graphite as the carbon source

We report on the growth of high-quality diamond using a microwave plasma chemical vapor deposition (CVD) system in which the feed gas contains no hydrocarbons, but instead the source of carbon is a graphite piece which resides within the plasma volume. Results of experiments using this technique by itself and in combination with the normal methane feed gas method are described. The samples were analyzed by Raman spectroscopy and scanning electron microscopy. Diamond grown in this way was found to be particularly pure and of high crystallinity.