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- Nguyen, Son Tien, et al.
(författare)
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Identification of a Frenkel-pair defect in electron-irradiated 3C SiC
- 2009
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 80, s. 125201-
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Tidskriftsartikel (refereegranskat)abstract
- Anelectron paramagnetic resonance (EPR) spectrum labeled LE1 was observed inn-type 3C SiC after electron irradiation at low temperatures (~80–100 K).A hyperfine interaction with four nearest C neighbors similar tothat of the well-known silicon vacancy in the negative chargestate was observed, but the LE1 center has a lowersymmetry, C2v. Supercell calculations of different configurations of silicon vacancy-interstitialFrenkel-pairs, VSi-Sii, were performed showing that pairs with a nearestneighbor Si interstitial are unstable—VSi and Sii will automatically recombine—whereaspairs with a second neighbor Sii are stable. Comparing thedata obtained from EPR and supercell calculations, the LE1 centeris assigned to the Frenkel-pair between VSi and a secondneighbor Sii interstitial along the [100] direction in the 3+charge state, V-Si. In addition, a path for the migrationof Si was found in 3C SiC. In samples irradiatedat low temperatures, the LE1 Frenkel-pair was found to bethe dominating defect whereas EPR signals of single vacancies werenot detected. The center disappears after warming up the samplesto room temperature.
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