Accession Number:

ADA280609

Title:

Diamond Deposition and Defect Chemistry Studied via Solid State NMR

Descriptive Note:

Final rept. 1 Jun 1990-30 Jun 1994

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING

Personal Author(s):

Report Date:

1994-06-30

Pagination or Media Count:

121.0

Abstract:

Diamond defects were quantified by nuclear magnetic resonance NMR. While maintaining the macroscopic integrity of the films, concentrations between 0.001 and 1.0 at. H were measured, among the lowest ever reported by solid- state 1H NMR. These concentrations were correlated to infrared absorption in the 8 to 10 micron region and to thermal conductivity. Despite the low concentrations. Multiple Quantum NMR reveals a high degree of hydrogen clustering consistent with grain boundary passivation. Most hydrogen is rigidly held, but some, probably in -OCH3 and -NCH3 defects, undergoes rotation at room temperature. Similar results were obtained for hot-filament, microwave-plasma and DC arc-jet films, suggesting a common surface chemistry, but no hydrogen was detected in an as-deposited combustion film. 13C NMR provided the first quantitative determination of non-diamond bonded carbon defects, providing a benchmark for Raman spectroscopy, the primary characterization method for diamond. Selective 13C labeling demonstrated heterogeneous reactions involving carbon occur at the hot-filament. With high-speed magic-angle-spinning 19F NMR, CFx x1-3 functionalities were resolved on the surface of plasma-treated diamond powder. Understanding these defects impacts the understanding of film growth mechanisms and structure-property relationships for CVD diamond. Diamond, NMR, CVD, Defects, Thin films, Isotopic substitution.

Subject Categories:

  • Crystallography
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE