We report on an irradiation-induced photoluminescence ͑PL͒ band in 4H and 6H SiC and the corresponding optically detected magnetic resonance ͑ODMR͒ signals from this band. The deep PL band has the same number of no-phonon lines as there are inequivalent sites in the respective polytype. These lines are at 1352 and 1438 meV in the case of 4H and at 1366, 1398, and 1433 meV in the case of 6H. The intensity of the PL lines is reduced after a short anneal at 750°C. ODMR measurements with above-band-gap excitation show that two spin-triplet (Sϭ1) states with a weak axial character are detected via each PL line in these bands. One of these two triplet states can be selectively excited with the excitation energy of the corresponding PL line. These triplet signals can therefore be detected separately and only then can the well documented and characteristic hyperfine interaction of the silicon vacancy in SiC be resolved. Considering the correlation between the irradiation dose and the signal strength, the well established annealing temperature and the characteristic hyperfine pattern, we suggest that this PL band is related to the isolated silicon vacancy in 4H and 6H SiC. The spin state (Sϭ1) implies a charge state of the vacancy with an even number of electrons. By combining the knowledge from complementary electron-spin resonance measurements and theoretical calculations we hold the neutral charge state for the strongest candidate.

Annealing behavior between room temperature and 2000°C of deep level defects in electron-irradiated n -type 4H silicon carbide J. Appl. Phys. 98, 043518 (2005); 10.1063/1.2009816 Deep levels created by low energy electron irradiation in 4 H -SiC A deep level transient spectroscopy study of electron irradiation induced deep levels in p-type 6H-SiCDeep level defects in electron-irradiated 4H SiC epitaxial layers grown by chemical vapor deposition were studied using deep level transient spectroscopy. The measurements performed on electron-irradiated p ϩ n junctions in the temperature range 100-750 K revealed several electron traps and one hole trap with thermal ionization energies ranging from 0.35 to 1.65 eV. Most of these defects were already observed at a dose of irradiation as low as Ϸ 5ϫ10 13 cm Ϫ2 . Dose dependence and annealing behavior of the defects were investigated. For two of these electron traps, the electron capture cross section was measured. From the temperature dependence studies, the capture cross section of these two defects are shown to be temperature independent.

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Point defects in solids promise precise measurements of various quantities. Especially magnetic field sensing using the spin of point defects has been of great interest recently. When optical readout of spin states is used, point defects achieve optical magnetic imaging with high spatial resolution at ambient conditions. Here, we demonstrate that genuine optical vector magnetometry can be realized using the silicon vacancy in SiC, which has an uncommon S ¼ 3=2 spin. To this end, we develop and experimentally test sensing protocols based on a reference field approach combined with multifrequency spin excitation. Our work suggests that the silicon vacancy in an industry-friendly platform, SiC, has the potential for various magnetometry applications under ambient conditions.

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