Two sets of prominent photoluminescence lines, termed A and B here, in electron-irradiated and ion-implanted 4H-SiC were investigated using low-temperature photoluminescence microscopy. From their spectral details, temperature dependence, emission energies and annealing characteristics, it was concluded that they arose from the neutral on-axis and off-axis carbon antisite-vacancy pairs (VCCSi)0. Photoluminescence excitation spectroscopy was used to derive an energy-level diagram for the B set of lines of 4H-SiC. The creation of these centers was demonstrated as a process that was sensitively dependent not only on the n or p doping of the material, as was proposed but also on the temperature and the existence of inhomogeneous internal electric and strain fields. Samples of different purities from many different sources were studied. Relatively impure, highly compensated doped samples exhibited very strong A and B photoluminescence and were referred to as AB material. Purer materials, largely uncompensated, called V here, that were n(N) or p(Al) doped, have photoluminescence from Si vacancy related defects but relatively little A or B intensity even after annealing at 900C. Similar sets of photoluminescence lines have also been observed in ion-implanted 4H-SiC and electron-irradiated 6H-SiC and investigated to a more limited extent. A wide range of different electron-irradiation conditions was explored

Photoluminescence Study of the Carbon Antisite-Vacancy Pair in 4H- and 6H-SiC. J.W.Steeds: Physical Review B, 2009, 80[24], 245202