Optic and electronic properties of large band gap semiconductors doped by ion implantation

Various ions were implanted in SiC, and the photoluminescence was examined after the samples were annealed. Two luminescence spectra that were independent of the implanted ion persisted to the highest annealing temperature of 1700C. One, called D1, was attributed to di-vacancies. The other, called D2, was attributed to di-interstitials because of the number and intensity of high-energy localized modes in the spectrum. Unlike these pure defects, some sample-dependent defects were produced by electron bombardment, and were attributed to impurity-defect pairs. Severe lattice damage was absent in samples implanted with the light atoms H and D, which produced strong new spectra. The observation of C-H and C-D vibrational modes led to a model of the center that was confirmed by extensive magneto-optical measurements. Two charge states of the center were observed in luminescence. The center was produced by H- or D-implantation in polytypes 4H, 6H and 15R, but not in 3C. (Modified author abstract)