Isotope enriched diamond growth by chemical vapour deposition

Teraji, Tokuyuki*; Taniguchi, Takashi*; Watanabe, Kenji*; Koizumi, Satoshi*; Onoda, Shinobu; Oshima, Takeshi; Isoya, Junichi*

Homoepitaxial single crystal diamond films and polycrystalline diamond free-standing films were grown by means of microwave-assisted chemical vapour deposition (MPCVD). Methane that is isotopically controlled into C depleted gas was used as a source gas. In order to fulfil both the higher quality and higher growth rate, diamond films were grown under the high power MPCVD condition. It was found that the free exciton emission was intensively observed from the homoepitaxial diamond (100) films. This fact indicates the high quality of diamond films was obtained by this method. The free exciton emission was also detected from polycrystalline free-standing diamond, although the intensity was weaker than those of homoepitaxial film. These enriched diamond crystals are attracted for improving thermal conductivity and coherence time of nitrogen-vacancy (NV) centers.