Photoluminescence, thermally stimulated luminescence and their photo-excitation spectra in hexagonal-type SiC were studied between 5 and 300K. A thermally stimulated luminescence glow peak which was related to Ti was observed close to 140K in compensated 6H–SiC crystals with the corresponding thermal ionization energy of a trap close to 0.170eV. The spectral distribution of thermally stimulated luminescence had a maximum at 1.8eV in 6H–SiC and at 2.43eV in 4H–SiC. A specific structure in the photo-excitation spectrum of photoluminescence close to the exciton gap (3.023eV) was revealed only in 6H–SiC material. This revealed an essential role of excitons in resonance energy transfer to the Ti-related centers in SiC. The results were explained in terms of a model for iso-electronic centers composed of individual Ti atoms or a Ti–N pair which represented a complex involving an electronic trap and a recombination center.

Luminescence Characterization of Titanium-Related Defects in 6H–SiC. Y.M.Suleimanov, I.Zaharchenko, S.Ostapenko: Physica B, 2001, 308-310, 714-7