C-13 NMR-STUDY OF CVD DIAMONDS

Chemical vapor deposition (CVD) diamond films were deposited by direct current methane-hydrogen-argon plasma jet on a molybdenum plate. The C-13 nuclear magnetic resonance (NMR) spectra were measured either by static or magic angle spinning (MAS) procedure on CVD diamond, natural diamond, and high pressure-high temperature synthetic diamond. Two na rrow peaks were observed on the CVD and the natural diamonds similarly in static NMR and were scarcely affected by magic angle spinning. On the other hand, only one broad peak was observed in high pressure-high temperature synthetic diamond, the broadening being ascribed to the l attice distortion, Spin-lattice relaxation time, T1, was extremely lon g in natural diamond and rather short in high pressure-high temperatur e synthetic diamond. The CVD diamond showed an intermediate T1. It was found from C-13 NMR spectroscopy that CVD diamond well resembled the natural diamond.