Characterization of Diamond Powders by Electron Paramagnetic Resonance, X-Ray Photoelectron Spectroscopy and Electron Energy Loss Spectro
P S. Wang, Stephen M. Hsu, T N. Witberg
Paramagnetic defects in diamond powders were examined by x-band electron paramagnetic resonance (EPR) for dangling bonds and unpaired electrons at 9.62 GHz. Strong spin centers were detected in all powders near gnearly equal to} 2.0026 region. In some powders, a second spin center was observed with a signal pattern of spin-spin interaction of randomly oriented powder form with αxx=αyy<α22. Gravimetric analysis showed that the oxidation kinetics are in good agreement with those which have been observed for diamond films and diamond crystals. The activation energy for oxidation in air was measured to be (196 13) kJ/mol in the temperature range from 650 C to 730 C. X-ray photoelectron spectroscopy (XPS) analysis of the oxidized powders showed an increase in a lower binding energy C 1s component relative to the as-received powder. This lower energy C 1s peak, at about 283 eV, is attributed to amophous carbon or graphite. Surface plasmon electron energy loss spectroscopy (EELS) showed that on the oxidized diamond powders, there was an increase in the plasmon loss peak at about 23 eV as compared to the as-received powder. This 23 eV loss peak is in good agreement with the reported plasmon loss energy for amorphous carbon.
Journal of Materials Science
diamond powders, electron energy loss spectroscopy, electron paramagnetic resonance, x-ray photoelectron spectroscopy
, Hsu, S.
and Witberg, T.
Characterization of Diamond Powders by Electron Paramagnetic Resonance, X-Ray Photoelectron Spectroscopy and Electron Energy Loss Spectro, Journal of Materials Science
(Accessed December 4, 2023)