Applied Physics Letters · 1992 · 65 citations · 6 references
Natural SciencesMaterials EngineeringMaterials ScienceCrystal StructureMaterials ChemistrySpectroscopyInfrared SpectroscopyMagnetic Resonance SpectroscopyNuclear SpectroscopyOptical Properties Of SolidsOptical SpectroscopyResonance AbsorptionAbsorption StudiesGrain BoundariesInfrared Absorption LinesInfrared Absorption SpectroscopyNuclear Magnetic Resonance StudiesOptical AbsorptionOptical Absorption SpectraSolid-state Nuclear Magnetic Resonance Spectroscopy
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.
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