Samples of 6H-SiC were electron-irradiated with electron energies in the range of 100 to 300keV, in a transmission electron microscope. After irradiation, the samples were transferred to microscopic low-temperature photoluminescence spectrometers and were excited by using 325, 488 and 514.5nm lasers. Optical centers were observed that had high-energy local modes and, when samples that had been enriched with 13C during growth were examined, these local modes were found to be split into triplets. The observations were interpreted as being due to C-C dumb-bells created from C interstitials generated during the irradiation process. This was the first reported identification of self-interstitial atoms by photoluminescence in SiC.

Identification of Carbon Interstitials in Electron-Irradiated 6H-SiC by Use of a 13C Enriched Specimen. G.A.Evans, J.W.Steeds, L.Ley, M.Hundhausen, N.Schulze, G.Pensl: Physical Review B, 2002, 66[3], 035204 (9pp)