Analysis of donor–acceptor pairs and titanium related luminescence in different compensated 6H–SiC single crystals

The photoluminescence of three kinds of compensated 6H–SiC single crystals, the vanadium heavily compensated, vanadium slightly compensated, and non-vanadium compensated, has been investigated. Nitrogen (N), aluminum (Al), vanadium (V), and titanium (Ti) are the main impurities. For the vanadium heavily compensated and non-vanadium compensated semi-insulating 6H–SiC, photoluminescence of the donor–acceptor pairs (DAPs) are inconspicuous because of the rare shallow centers. For vanadium slightly compensated 6H–SiC, DAPs and Ti-related emissions are obvious. As an effective luminescence center, the Ti-related recombinations cover a broad range from 1.70 eV to 2.86 eV.