Photo-EPR studies on the AB3 and AB4 nickel-related defects in diamond

摘要

We present electron paramagnetic resonance (EPR) and photo-EPR investigations on the AB3 and AB4 centers found in synthetic diamond crystals. We observed a strong increase of the AB4 EPR signal intensity when diamond samples were illuminated with monochromatic light for photon energies hv > 2.06+-0.02eV. Additionally, a quenching of the AB3 signal intensity was observed for photoexcitations at hv > 2.26 +-0.02 eV. The nature of the physical processes responsible for the observed photoinduced changes in both centers is discussed.