Defects, doping, and conduction mechanisms in nitrogen-doped tetrahedral amorphous carbon
- Department of Physics and Astronomy and Condensed Matter and Surface Sciences Program, Ohio University, Athens, Ohio 45701-2979 (United States)
- Department of Physics, Washington University, St. Louis, Missouri 63130 (United States)
First principles methods are used to study N doping of diamondlike amorphous carbon. A structural model containing 216 atoms is introduced, whose properties are in agreement with the available experimental data. The topological and electronic properties for different N doping concentrations are investigated. We find that N occurring in tetrahedral sites or chains of an even number of {pi} bonded sites results in an increase of the Fermi energy, while N incorporation in strained network sites induces structural changes that lead to an increase in the sp{sup 2} fraction of the material. The prevalent conduction mechanisms are identified and discussed. While the Fermi energy increases upon N doping, the localization of the conduction-band-tail states limits extended state conduction. These results are compared to the recent experimental reports on N doping of ta-C and we find that the nondoping threefold N incorporation (N{sub 3}{sup 0}) is energetically most likely, which explains the low doping efficiency seen in experiments. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 450228
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 3; Other Information: PBD: Feb 1997
- Country of Publication:
- United States
- Language:
- English
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