Nuclear magnetic resonance and infrared absorption studies of hydrogen incorporation in polycrystalline diamond

Publisher Website
Google Scholar
Abstract
Hydrogen incorporated into polycrystalline diamond was found to correlate with the optical absorption in the 8 to 10 μm wavelength IR region, where transparency is desired. In this first detailed study of diamond films by 1H NMR, average concentrations were found to be <0.25 at. % H. However, segregation produces regions of extremely high local hydrogen density as evidenced by a broad (50–70 kHz) Gaussian NMR component. The majority of this clustered hydrogen is rigidly held, while a fraction undergoes motional narrowing at room temperature, most likely due to methyl group rotation. Sites at grain boundaries are capable of accounting for a significant fraction of this hydrogen, as are defects and voids within the crystal or a heavily hydrogenated phase stable at the deposition temperature.