| 1. |
- Carlsson, Patrick, 1975-, et al.
(författare)
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Photo-EPR Studies on Low-Energy Electron-irradiated 4H-SiC
- 2009
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Ingår i: Materials Science Forum, Vols. 615-617. - Materials Science Forum Vols. 615-617 : Trans Tech Publications. - 9780878493340 ; , s. 401-404
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Konferensbidrag (refereegranskat)abstract
- Photoexcitation electron paramagnetic resonance (photo-EPR) was used to determine deep levels related to the carbon vacancy (VC) in 4H-SiC. High-purity free-standing n-type 4H-SiC epilayers with concentration of intrinsic defects (except the photo-insensitive SI1 center) below the detection limit of EPR were irradiated with low-energy (200 keV) electrons to create mainly VC and defects related to the C sublattice. The simultaneous observation of and signals, their relative intensity changes and the absence of other defects in the sample provide a more straight and reliable interpretation of the photo-EPR results. The study suggests that the (+|0) level of VC is located at ~EC–1.77 eV in agreement with previously reported results and its single and double acceptor levels may be at ~ EC–0.8 eV and ~ EC–1.0 eV, respectively.
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| 2. |
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| 3. |
- Isoya, J., et al.
(författare)
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EPR Identification of Defects and Impurities in SiC : To Be Decisive
- 2009
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Ingår i: Materials Science Forum, Vols. 600-603. - : Trans Tech Publications. ; , s. 279-284
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Konferensbidrag (refereegranskat)abstract
- In EPR (electron paramagnetic resonance) identification of point defects, hyperfine (HF) interaction is decisive information not only for chemical identity but also for the local geometry and the electronic state. In some intrinsic defects in SiC, the wave function of the unpaired electron extends quite unevenly among major atoms comprising the defects. In such a case, the determination of the number of equivalent atoms and the chemical identity (Si or C) of those atoms even with weak HF splitting are useful to compare with HF parameters obtained theoretically. For vacancy-related defects of relatively deep levels, the sum of the spin densities on the nearest-neighbor shell is found to be 60-68%.
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| 4. |
- Nguyen, Son Tien, 1953-, et al.
(författare)
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Defects introduced by electron-irradiation at low temperatures in SiC
- 2009
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Ingår i: Materials Science Forum Vols. 615-617. - : Trans Tech Publicarions. - 9780878493340 ; , s. 377-380
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Konferensbidrag (refereegranskat)abstract
- Defects introduced by electron irradiation at ~80-100 K in 3C-, 4H- and 6H-SiC were studied by electron paramagnetic resonance (EPR). A number of EPR spectra, labelled LE1-10, were detected. Combining EPR and supercell calculations, we will show that the LE1 center in 3C-SiC with C2v symmetry and an electron spin S=3/2 is related to the (VSi-Sii)3+ Frenkel pair between the silicon vacancy and a second neighbour Sii interstitial along the <100> direction. Results on other centers, possibly also related to interstitials, are discussed.
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