Electrical activity of isolated oxygen defects in SiC

A. Gali, D. Heringer, P. Deák, Z. Hajnal, Th Frauenheim, W. J. Choyke

Research output: Contribution to journalConference article

1 Citation (Scopus)


Ab initio LDA calculations have been carried out for the isolated oxygen impurity in 3C(cubic) and 4H(hexagonal) silicon carbide. Cluster models with localized basis functions were used to calculate vibrational frequencies and spin distributions while supercell calculations were used to determine the relative stabilities and occupancy levels. The substitutional oxygen has been studied in the 2+/+/0/-/2- charge states on both the C and Si site, and compared in stability to interstitial oxygen. It has been found that oxygen at the carbon site (Oc is the most stable defect and it is an on-center double donor in 3C-SiC. The characteristic vibration frequencies and the spin distributions for the paramagnetic state are given. OSi has a double donor level in the lower half of the band gap. Oi is also electrically active with complicated bonds. The similar behavior of the Oc has been found in 4H-SiC, however OSi is proven to be an amphoteric defect in 4H-SiC.

Original languageEnglish
Pages (from-to)463-466
Number of pages4
JournalMaterials Science Forum
Publication statusPublished - 2001

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Gali, A., Heringer, D., Deák, P., Hajnal, Z., Frauenheim, T., & Choyke, W. J. (2001). Electrical activity of isolated oxygen defects in SiC. Materials Science Forum, 353-356, 463-466. https://doi.org/10.4028/www.scientific.net/msf.353-356.463