Creation and identification of the two spin states of dicarbon antisite defects in 4H-SiC
- Department of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)
This paper deals with the positive identification by low-temperature photoluminescence microspectroscopy of the two spin states of the dicarbon antisites in 4H-SiC. The defects are created by high-dose electron irradiation at room temperature or by subsequent exposure to intense 325 nm radiation at temperatures up to 1300 deg. C. Identification was achieved by their formation and annealing characteristics, by the energies of their local vibrational modes, by the nature of their splitting in {sup 13}C isotope enriched samples, and by comparison with published results of ab initio local density approximation calculations. Four related but different forms of this defect have been predicted, two with S=0 and two with S=1, and their calculated properties are consistent with the experimental results presented here. The excitation processes for the optical centers within the irradiated region are quite unusual. For a 488 nm laser excitation, both spin states of the defect are observed by up-conversion. For a 325 nm excitation, the optical centers are only observed at the periphery of the high-dose irradiated regions after the sample has been exposed to an intense 325 nm beam. In this case, the optical centers are mainly in the S=0 state. The centers are eliminated by annealing in the range of 800-950 deg. C.
- OSTI ID:
- 21143547
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 77, Issue 19; Other Information: DOI: 10.1103/PhysRevB.77.195203; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
APPROXIMATIONS
CARBON 13
COMPARATIVE EVALUATIONS
CONVERSION
CRYSTAL DEFECTS
ELECTRON BEAMS
ELECTRONS
EXCITATION
IRRADIATION
LASER RADIATION
PHOTOLUMINESCENCE
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
SEMICONDUCTOR MATERIALS
SILICON CARBIDES
SPIN
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 1000-4000 K