Identification of carbon interstitials in electron-irradiated 6H-SiC by use of a13Cenriched specimen

Abstract

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