Digitale Medien
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
113 (2000), S. 7582-7587
ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
In this investigation we use B3LYP density functional theory (DFT) to investigate the CVD growth mechanism of (100) diamond. Our results are consistent with the Garrison mechanism in which the dimer-opening step involves simultaneous formation of a surface olefin and dissociation of the dimer. We calculate this step to have a barrier of 9.6 kcal/mol. The olefin is then attacked by a surface radical to form a six-membered ring. We find this reaction to be the rate-limiting step with an activation energy of 13.6 kcal/mol. This is in excellent agreement with the experimental value of 15 kcal/mol obtained by the selective growth method and XPS. The direct ring-opening and ring-closing reaction from adsorbed CH2 radical has an activation energy of 49.4 kcal/mol and does not contribute significantly to the growth rate. The barrier on larger clusters that include the effects of neighboring adsorbed hydrogen increases to 15.6 kcal/mol. Additionally, our calculated vibrational frequencies agree within 2% of experimental IR and HREELS spectra. © 2000 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.1311976
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